Please help this is my final exam

Which word or phrase best clarifies the relationship between the claim and the evidence?

Changing to a later school start time is an interesting idea, but it would cause too many problems. ________, if student athletes are playing sports until 6 or 7 p.m., those students will not have time to do their homework, and their academic performance is likely to suffer.

A. In this case

B. Surprisingly

C. Therefore

D. For example