What is an example of a specific mixture that could be separated with simple distillation and a specific mixture for which only fractional distillation would be used?

Question

I think a methanol-water mixture could be done with simple distillation, since they have b.p which are further apart. But what about the other one?

Answer 1

Crude oil is separated by fractional distillation but that may not satisfy the requirement of being a "specific" mixture.