Doing your homework is a sure way to improve your test scores and this is especially true

问题补充：

Doing your homework is a sure way to improve your test scores, and this is especially true it comes to classroom tests.

A. before

B. since

C. when

D. after

答案：

A. before

B. since

(答案→)C. when

D. after

解析：when it comes to意为当提到或谈到……。