选A.
The teacher was glad to take the student's advise to improve his teaching,which in turn made the students satisfied.
老师很乐意听取同学们的意见来改善他的教学,反过来,他的教学也让学生们很满意.
解析：in turn 依次；反过来,for sure 无疑；准保 ,in return.作为报答,on purpose 故意地,根据题意选A.
in return 没有反过来的意思.
祝开心~!