The correct answer is A) Refrigerants are heavier than air and displace oxygen. Refrigerants such as CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon) are denser than air. When they leak into a confined space or limited surroundings, they can displace the oxygen-rich air, leading to a lack of oxygen and potential suffocation. As the refrigerants accumulate in the space, they push out the breathable air, creating an oxygen-deficient environment that can be hazardous to human health. The other options are incorrect because: B) Refrigerants lighter than air would rise and not cause suffocation, C) the odor of refrigerants does not prevent breathing, and D) refrigerants do not contain acidic substances that would directly cause suffocation.