Conclusion: skateboarding is safer than jogging.
Prethinking: I think the comparison should be in % of people injured out of % of people jogged vs. % of people injured out of % of people used skateboard. Actually, only number comparison between two is flawed.
Which of the following indicates a flaw in the reasoning above?
A. It fails to distinguish professional skateboarders who attempt very dangerous maneuvers from amateurs who are comparatively cautious. -> Incorrect. We have to get flaw as "skateboarding is safer than jogging".
B. It assumes without warrant that no one who skateboards also jogs. -> Incorrect. how are we comparing with people, who jog.
C. It fails to consider the number of people who skateboard as compared with the number of people who jog. -> Yes! No. of people must be compared. Let's keep it.
D. It ignores the possibility that other activities cause even more injuries than either skateboarding or jogging. -> Incorrect. we are talking about the flaw in skateboarding is safer than jogging.
E. It fails to address the issue and instead attacks the character of the legislature. -> Incorrect.
So, I think C.