Answer: B. Crusoe's mental debate about sin
Step-by-step explanation:
Robinson Crusoe was stranded all alone on a deserted island and therefore had no one to talk to. The various experiences he went through led him to start reminiscing within himself of the various sins he had committed and led to various mental debates about sin.
This could therefore be said to be the antagonist in the story because in continually plaguing the thoughts of Crusoe, this debate went against him until he changed his ways and became more of a believer in God.