The correct answer is A. man vs. man.
There are many types of conflicts, but these four are the most common ones in literature:
A. man vs. man - this is a conflict between two people, where they fight or just generally disagree
B. man vs. society - when a group of people, or the entire society has a disagreement with the protagonist
C. man vs. himself - this is internal conflict, where the protagonist cannot come to terms with himself
D. man vs. nature - nature is overpowering man, and man cannot deal with that
Theseus fought Procrustes because he was killing people. This was Theseus's last adventure that he had to finish before arriving in Athens. Since the conflict is between two people, the correct answer is A.
