So running removes the pain of a broken ankle? (Also can be said about punching with a broken fist?)

Your 2nd part is right though. I checked the textbook (Meyers AP Psychology) - no specific mention of this scenario (only that pain can be blocked). I got the class to vote on what they chose as the right answer. More than half of the class chose C (and these were the consistently high-scoring students). I read a dozen articles and a rewatched that lecture from Duke where I initially learned the concept. Nothing to suggest that more pain = no pain, only that small pain can be alleviated by consistent non-noxious stimulus.

I know that D is wrong already. I was asking for a more professional clarification of what I understand on a basic level.