The correct answer is option 'A' - Kolkata-Delhi.

The National Highway, also known as the Grand Trunk Road, is one of the oldest and longest road networks in India. It stretches across several states, connecting various important cities and towns. Let's delve deeper into why option 'A' is the correct answer:

The Grand Trunk Road:

The Grand Trunk Road, also referred to as NH 19, is a significant highway that runs through India, Pakistan, and Bangladesh. It has a rich history dating back to the Mauryan Empire and has been an important trade route for centuries. In India, it stretches from Kolkata in West Bengal to Delhi, covering a distance of approximately 1,500 kilometers.

Option A: Kolkata-Delhi:

Kolkata, the capital of West Bengal, is located in the eastern part of India. It is a major commercial, cultural, and educational center of the country. On the other hand, Delhi, the capital of India, is situated in the northern part of the country. It serves as the political and administrative hub of the nation.

Significance of the Grand Trunk Road:

1. Historical Importance:
- The Grand Trunk Road holds immense historical significance as it was built during the reign of Emperor Sher Shah Suri in the 16th century.
- It served as a crucial trade route during the Mughal era, connecting various cities and towns.
- It facilitated trade and cultural exchange between different regions and played a vital role in the growth and development of these areas.

2. Economic Importance:
- The Grand Trunk Road continues to be an important economic artery, linking major industrial and commercial centers.
- It facilitates the movement of goods and services, contributing to the overall economic development of the regions it passes through.
- The road also provides connectivity to several ports, railway stations, and airports, enhancing trade and commerce.

3. Cultural and Touristic Significance:
- The Grand Trunk Road is not only a transportation route but also a cultural corridor, reflecting the diverse heritage and traditions of India.
- It passes through several historically significant cities, towns, and tourist destinations, attracting visitors from all over the world.
- The road is adorned with various landmarks, monuments, and historical sites that showcase the rich cultural tapestry of the country.

In conclusion, the National Highway, also known as the Grand Trunk Road, connects Kolkata and Delhi. This road holds immense historical, economic, cultural, and touristic importance, serving as a lifeline for trade, transportation, and cultural exchange.