Though the population of Arab Southwest Asia is small, this region still plays an important part in world affairs. Why? A. Oil wealth and their role in the Arab-Israeli peace process B. They have democratic governments and strong trade policies. C. Agricultural output and the fact that they're Westernized D. Oil wealth and the fact that they're Westernized

Most likely to be D.

of course this will be a personal choice.

if you think through it by option:

A - cannot be A as the thing with arab-Isreal peace is not really relevant every where else, if these countries are happy or not, the rest of the world is indifferent.

B - they are not democratic ... most of them live under dictatorships

C - very possible ... however, their agriculture is not very strong and they rely heavily on their oil resources, so probably not this one

D - they are oil rich, they are wealthy, not sure about westernised, but out of your options, this one seems more plausible