37) What is a cross -connection? A. Threade d faucet B. Device that prevents a vacuum C. Valve that mixes hot and cold water D. Link between sources of safe and dirty water

The correct answer is D. A cross-connection refers to a link between sources of safe and dirty water. It occurs when there is a potential for non-potable water to come into contact with the potable water supply, which can lead to contamination and pose a risk to public health.