PLS HELP ASAP!!!

In "A Horseman in the Sky," Carter Druse remembers his father's command that he should always do his duty. How do the words of Carter's father affect Carter and advance the story's plot?

AThey lead to Carter's decision to shoot the horseman.

BThey result in Carter's hatred for his father.

CThey cause Carter to join the Union army.

DThey persuade Carter to hide the truth about his father.