The correct answer is option D, Ganga.

Explanation:
The Ganga, also known as the Ganges, is a major river in the Indian subcontinent that flows through the kingdom of Magadha. Here is a detailed explanation of why the Ganga and its tributaries flow through the kingdom of Magadha:

1. Geographical Location:
The kingdom of Magadha was situated in the eastern part of the Indian subcontinent, in present-day Bihar and parts of Uttar Pradesh. The Ganga River flows through this region, making it an important waterway for the kingdom.

2. Importance of the Ganga River:
The Ganga River is one of the most sacred rivers in Hinduism and is considered the lifeline of the region. It has been a significant source of water, transportation, and irrigation for centuries. The fertile plains along the banks of the Ganga have supported agriculture and human settlements, making it an ideal location for the kingdom of Magadha to flourish.

3. Tributaries of the Ganga:
The Ganga River has several tributaries, which are smaller rivers or streams that flow into it. Some of the important tributaries of the Ganga include the Yamuna, Son, Gandak, Kosi, and Ghaghara rivers. These tributaries not only contribute to the flow of water in the Ganga but also bring fertile soil and nutrients to the region, making it suitable for agriculture.

4. Historical Significance:
The kingdom of Magadha was an important political and cultural center in ancient India. It was the birthplace of several influential dynasties, such as the Mauryas and the Guptas. The Ganga River played a crucial role in the development of trade and commerce in the region, as it provided a means of transportation for goods and people. The river also facilitated cultural exchange and the spread of religion, with many important religious sites located along its banks.

In conclusion, the Ganga River and its tributaries flow through the kingdom of Magadha due to its location in the eastern part of the Indian subcontinent. The river has been of great significance to the region, providing water, transportation, and fertile land for agriculture. Its historical and cultural importance has made it an integral part of the kingdom's development and prosperity.

The correct answer is option D) Ganga.

The Ganga River, also known as the Ganges, is one of the major rivers in India and its tributaries flow through the kingdom of Magadha. Here's an explanation of why the Ganga River is the correct answer:

1. Introduction:
The Ganga River holds immense significance in Indian history, culture, and mythology. It is considered sacred by Hindus and is often referred to as the "Maa Ganga" or Mother Ganges. The river has played a vital role in the development of ancient civilizations and kingdoms, including Magadha.

2. The Kingdom of Magadha:
Magadha was one of the most powerful and prosperous kingdoms in ancient India. It was located in the eastern part of the Indian subcontinent, in present-day Bihar and Jharkhand. Magadha emerged as a prominent kingdom during the 6th century BCE and witnessed the rise of several important dynasties, such as the Haryanka and Maurya dynasties.

3. Geographical Location:
Magadha was situated in the fertile Gangetic plains, which are formed by the Ganga River and its tributaries. The kingdom benefited from the river's water for irrigation, transportation, and trade. The Ganga River, with its vast network of tributaries, provided the necessary resources and support for the growth and prosperity of the kingdom.

4. Importance of the Ganga River:
The Ganga River is known for its immense cultural, religious, and economic significance. It is considered a lifeline for the people living in its vicinity. The river not only provides water for irrigation and drinking purposes but also supports a thriving ecosystem. The fertile plains around the river are ideal for agriculture, making it an agricultural hub.

5. Impact on Magadha:
The presence of the Ganga River and its tributaries had a profound impact on the kingdom of Magadha. The river facilitated trade and commerce, allowing the kingdom to flourish economically. It also served as a means of transportation, connecting Magadha with other regions of India.

6. Cultural and Religious Significance:
The Ganga River holds great religious significance for Hindus. It is believed to have purifying properties, and taking a dip in its holy waters is considered spiritually cleansing. Many important religious ceremonies and festivals, such as the Kumbh Mela, are held on the banks of the Ganga. The river has also been mentioned in various ancient texts and scriptures, adding to its cultural and religious importance.

In conclusion, the Ganga River and its tributaries flow through the kingdom of Magadha. The river not only provided essential resources for the kingdom's development but also played a significant role in shaping the cultural and religious landscape of the region.