편입 논리문제입니다

I felt more satistifed and at peace with myself than I had in a long time. I needed to learn to

open my heart and give love without requiring anything                                                  .

 a. to repay        b. to concern about            c. in return          d. in turns

답은 c 번이라고 하는데요 왜 a번은 안되나요??

I needed to learn to open my heart and give love without requiring anything                      .

                                                                        전치사  (목)require +목       목.보 to RV

이런구조로   a.번을 답으로 하면 안될까요?? 혹시 repay 뒷구조에 문제가 있어서일까요???