Question

If an employee notices that a bucket with sanitizing water is becoming dirt, he/she should ___.

Answer 1

This is pretty much a "common sense" question.  It'd be best to get rid of the dirty sanitizing water and start fresh; in other words, he should change (throw out) the dirty water and make a fresh sanitizer.

By the way, this is the Math section; next time, please choose a different section more suited to your questions.