Introduction:
India is known for having one of the largest road networks in the world. The length of this road network is measured in kilometers and is constantly expanding to cater to the growing population and increasing transportation needs. The length of India's road network is periodically updated to reflect the current infrastructure.

Answer:
The correct answer is option 'A', which states that the length of India's road network as of 2014-15 is 54.7 lakh km.

Explanation:
Here, we will break down the answer and explain it in detail.

1. Definition of lakh:
In India, the term "lakh" is commonly used to express large numbers. 1 lakh is equal to 100,000. Therefore, 54.7 lakh km is equivalent to 5,470,000 km.

2. Length of India's road network:
As of 2014-15, the length of India's road network was estimated to be 54.7 lakh km or 5,470,000 km. This includes national highways, state highways, district roads, and rural roads.

3. Factors contributing to the large road network:
India's vast road network can be attributed to several factors:

- Geographical diversity: India is a vast country with diverse landscapes, from mountains to plains, which requires an extensive road network to connect various regions.
- Population: India has a large population, and the road network is essential for transportation and connectivity.
- Economic growth: India's rapid economic growth has led to increased infrastructure development, including the expansion of the road network.
- Urbanization: The migration of people from rural areas to urban centers has necessitated the construction of roads to accommodate the growing population.

4. Importance of a large road network:
A large road network has several advantages:

- Connectivity: It improves connectivity between various regions, facilitating the movement of people, goods, and services.
- Economic development: A well-developed road network promotes trade and commerce, boosts tourism, and attracts investment, leading to overall economic development.
- Accessibility: It ensures accessibility to remote areas, enabling the delivery of essential services like healthcare, education, and emergency response.
- Employment generation: The construction and maintenance of roads create employment opportunities, both directly and indirectly.

Conclusion:
India's road network is one of the largest in the world, measuring 54.7 lakh km as of 2014-15. This extensive network plays a crucial role in connecting people, facilitating economic growth, and improving accessibility to different parts of the country.