Write a question about the following article.

There 's one spot on the trail that 's exposed and this is the part - at the beginning and end - that really challenged me . By the end , my legs felt fine , I was breathing steady , but my head started to do that thing it does when the sun and heat are too much . I ' ve felt this before , after having the brilliant idea to run up a small rocky " mountain " in 100 degree temperatures .

Question:
What may be their problem with the clearing on the trail ?
Select from the following.
[I] They forgot sunscreen .
[II] The sun blinds them .
[III] None of the above choices .
[IV] It makes them see double .