Which sentence shows the BEST use of a coordinating conjunction?

Question

Responses
A She paid for the extra ticket, so please pay her back.She paid for the extra ticket, so please pay her back.
B She paid for the extra ticket because Joe didn't bring money.She paid for the extra ticket because Joe didn't bring money.
C She paid for the extra ticket as if she knew Joe had no money.She paid for the extra ticket as if she knew Joe had no money.
D She paid for the extra ticket so that both kids could see the play.She paid for the extra ticket so that both kids could see the play.

Answer 1

A She paid for the extra ticket, so please pay her back.