Answer:
Correct answer is: (A) India, Pakistan, Nepal, and other countries are on a tectonic plate that collided with Asia 50 million years ago.
Explanation:
Mentioned countries are located on Indian Plate, tectonic plate which separated from ancient supercontinent Gondwana, some 100 million years ago. That supercontinent was on the Southern Hemispehere. Indian plate moved towards north, until colided with Eurasian plate, some 50 million years ago.
In the line of collision, continental convergent margin is formed, which eventually lead to formation of the Himalayas, highest mountian chain in the world.