Mark ____ in China for 10 years and now he teaches Chinese in Britain.A.has worked B.worked C.had

Mark ____ in China for 10 years and now he teaches Chinese in Britain.A.has worked B.worked C.had
Mark ____ in China for 10 years and now he teaches Chinese in Britain.
A.has worked B.worked C.had worked D.is working
选B还是选C？给出理由。