2. The chlorine in the solution used to sanitize food contact surfaces must be at what concentration?
A. You must use a capful of chlorine for every gallon of water.
B. The concentration of chlorine is not important.
C. The concentration must be between 50 and 100 parts per million, which can be measured with a chlorine paper test strip.
D. The concentration must be at 200 parts per million, which can be measured with a chlorine paper test strip.