What stretches over most of the arabian peninsula?

I believe the answer is: The Desert

From the whole geographical area of the arabian Peninsula, more than 90% of them is dessert. This made the countries across this region to have competitive disadvantage in producing good quality agricultural product, but they obtain a lot of oil reserves in exchange.

the correct answer on edgen is:

(c.) prevent the spread of communism.

i just took the test.