Answer:
b. The terrain is mostly desert and mountains
Step-by-step explanation:
Afghanistan has proved to be one of the hardest territories to invade, both throughout history and in more recent times. There are two main reasons for this, high mountains and deserts. The geography of Afghanistan has made every army thick twice before attacking. Even if an army has decided to invaded it, it was going to find it extremely hard to pass through the very high and dangerous mountains. If the mountains were crossed successfully, then it was a desert that was waiting for it. Most of the country is in a rain shadow, so it is very dry. The deserts are vast, with little to now eatable vegetation, and very few water sources. The temperatures at summer are very high and there's nowhere to hide from the sun, while in winter it is very cold and again there is no proper shelter from it. Before any army managed to actually launch an attack on the Afghan people it would have been so badly damaged that it will not be able to make an invasion.