The difference between the split ring commutator in a DC motor and the slips rings in an AC generator can be tricky. The split ring makes changes in the rotation every so often. A slip ring just stays in place and is only used as a connector. So a slip ring is for DC, whereas the split ring is used for AC.
The answer is C. The story never had anything about prison, and the story clearly states that the doctor was there. also the doctor didn't seem to bother the man he only passed by. SO C is your only logical answer
Temptation can lead those in power corruption.