Assertion: There is regional variation in the density of rural roads in India.
Reasoning: The density of rural roads is influenced by the nature of the terrain.

Both Assertion (A) and reasoning (R) are correct, and R is the correct explanation of A.

These roads are vital for providing links in rural areas. About 80 per cent of the total road length in India is categorised as rural roads. There is regional variation in the density of rural roads because these are influenced by the nature of the terrain.