Heat Cramps, since the sharp pains in his legs are cramps caused by the amount of time spent in the sun, and also from the heat, he is perspiring, which is making him dehydrated. You cramp when you're dehydratedz
Following your instincts is not what a critical think should do.
In the arteries. You know, that's your main blood passages
1. D
2. B
3. B
these are what i would go with sorry if they are wrong :)