How Did the Civil War in El Salvador Come to an End

How did the Civil War in El Salvador come to an end?

A) The U.S. backed army defeated the FMLN rebels and eliminated them as a poltical force
B) The FMLN defeated the army and began to implement its programs of social and economic change
C) The FMLN and government arrived at an internationally mediated, negotiated end, with neither side fully winning
D) U.S. marines invaded, forced both sides to accept a cease fire, and organized new elections