Swimmers are required ( ) or make loud noises when they are in

Swimmers are required ( ) or make loud noises when they are in the swimming pool.
A、to not dive
B、to dive
C、not to dive
D、not diving
【正确答案】：C
【题目解析】：be required not to do sth. 被要求不做某事。句子含义是在泳池，游泳者被要求不要潜水或者发出巨大响声。