Explanation:

Context:
This question is related to the year 2004.

Key Points:
- In 2004, the Indian National Congress led by Sonia Gandhi emerged victorious in the General Elections.
- The Congress party secured a total of 145 seats in the Lok Sabha, making it the single largest party.
- This victory led to the formation of the United Progressive Alliance (UPA) government with support from various regional parties.
- Dr. Manmohan Singh was appointed as the Prime Minister of India in 2004.
- This marked the beginning of the UPA government's rule in India, which lasted for two consecutive terms until 2014.
- The UPA government implemented various social welfare schemes and economic policies during its tenure.
- The year 2004 was significant in Indian politics as it brought about a change in the ruling party at the center.

Correct Answer:
Option 'B' is the correct answer because it correctly identifies the political event that took place in 2004, which was the formation of the UPA government after the Congress party's victory in the General Elections.