Which detail from the passage supports the claim that athletes are most affected by the summer temperatures? I really need this right!!!

A. Although athletes can be spared from the heat by playing indoors, many sports require a larger outdoor field.

B. Nearly 10,000 athletes are said to have had to seek medical attention because of the extreme heat.

C. Many high school athletes are in excellent shape during the summer.

D. Because of this, athletes are exposed to the high temperatures for long periods of time.