What are the effects of dehydration on health and sports performance?

I- The dehydration mechanism not only cools the body, but also causes a significant loss of fluids.
II- Progressive dehydration during exercise is frequent because athletes often do not ingest enough liquid to replace water losses.
III- The increase in dehydration can manifest itself with muscle cramps, apathy, weakness, and disorientation.
IV- In cold climates, dehydration can also occur, although less frequently.
a) Only I and II are correct.
b) Only II and III are correct.
c) Only III and IV are correct.
d) I, II, III, and IV are correct.