In Order to Determine the Effectiveness of His New Teaching

In order to determine the effectiveness of his new teaching method,Mr.Lewis gave his students a test to measure their knowledge before he implemented his new method.He also tested them after he implemented his new teaching method.Mr.Lewis is using a

A) single-group posttest only design.
B) non-equivalent control group posttest only design.
C) single-group pretest-posttest design.
D) non-equivalent control group pretest-posttest design.