Before a competition, you should not a. try anything new with food. b. have a liquid meal replacement. c. eat well the day before. d. overhydrate. it is not d.

Before you start a competition, do not try anything new with foods, as you do not know how your body will react, and also if it's a sport, you will most likely get sick and vomit due to the exercising and sudden movements.
Your answer is A.)
I hope this helps!

They need to know because sometimes they have a symptom