Which sentence contains a dependent clause?

A.James Madison was new to the presidency, but Dolley had already fulfilled some of the First Lady’s duties.

B.President Madison always praised Dolley for her keen political advice.

C.Since James Madison served as president from 1809 to 1817, Dolley Madison was one of the earliest First Ladies.

D.Dolley was famous for her hospitality, serving as a hostess for many White House parties.