Which of the following explains why there were no land routes for a direct passage from Delhi to Dunhuang?

Political tensions between India and China made it very risky to travel between the two cities.

There were too many rivers to cross between the two cities.

High mountains between the two cities made land travel difficult and time-consuming.

Both cities produced many of the same goods, so there was little need for trade between them.

High mountains between the two cities made land travel difficult and time-consuming.

Explanation:

There is the great mountains of the Himalayas that cut in half the passage by land from Delhi to Dunhuan that's why there was no land routs for a direct passage from Delhi to Dinhuang, having to climb the mountains or surround them was too difficult and time consuming, that's why it was easier to go through other route to the east and the going north th Dunhuang.