The “middle belt” describes the a. spread of islam through the middle east and north africa b. physical line dividing ireland into north and south c. imaginary line dividing nigeria into north and south d. blending of traditional african beliefs with the islamic faith

 The term "Middle Belt" refers to the geography of Nigeria and it refers to the middle part of it, inhabited by many enthic minorities.

It splits the North, which is Muslim and the South, which is largely Christian.

So the correct answer is:
C. imaginary line dividing Nigeria into north and south

Aregion is an area of land that has common features. these features can be natural, such as climate or landscape. they can also be artificial, such as language or religion. the xinjiang uyghur autonomous region, above, is an area of china inhabited by uyghurs, a muslim group with ethnic ties to turkish people.