Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the "Danger Zone.
I believe the answer to this question is C.
It is true that it is best to eat within an hour of exercising. You shouldn't eat before exercising, so as not to throw up, but you can do it afterwards.