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

That is false the sun’s core does not fusion