North africa/southwest asia
-the region is mainly islamic.
-water is a scarce resource.
-oil is an important commodity.

which best replaces the question mark?
a) region is usually peaceful.
b) climate is mostly mediterranean.
c) population is evenly distributed.
d) arabic is the most common language.

Let's name some countries in this region:
Algeria, Egypt, Saudi Arabia, Qatar, Kuwait, Tunisia, Lebanon- all of them are countries in which Arabic is the main Language!

So the correct answer is D) Arabic is the most common language. There are some exceptions, and other langauges such as Kurdish, Berber and Hebrew are also spoken there though.

Idon't know. the question you are trying to ask doesn't make sense.