in 과 on 도데체 차이점이 뭔가요???

When Carl met his wife at the airport, he ____ .

(A) gave a kiss to her cheek.
(B) gave a kiss her on the cheek
(C) gave her a kiss in the cheek. (D) gave her a kiss on the cheek 여기서 저는 정답으로 C를 골랐는데요.. 답이 D라네요.. 전치사 on과 in의 차이가 뭡니까??