Answer:
b) Caucasus
Step-by-step explanation:
Caucasus mountains are occupying the place between Europe and Asia, going from the Black Sea and the Caspian sea. As Afghanistan is in central Asia, we can conclude that the Caucasus is on the west of the country - all the mentioned elements (Europe, Caspian, and Black sea) are located on the west side of Afghanistan.
Ural mountains are in Russia, on the north side of Afghanistan.
Kunlun mountains are located in central China, which means it is located on the east compared to the position of Afghanistan.
Altai mountains are located in Mongolia, which is north-east of Afghanistan.