The correct answer is A) Refrigerants are heavier than air and displace oxygen. Refrigerants such as CFC (chlorofluorocarbons) and HCFC (hydrochlorofluorocarbons) are denser than air. If they leak into a confined space or area with limited ventilation, they can displace the oxygen-rich air, leading to a potentially dangerous situation where there is insufficient oxygen to breathe. This can cause suffocation, as the refrigerant gas occupies the space that would normally be filled with breathable air. The other options are incorrect because: B) Refrigerants lighter than air would rise and not displace oxygen; C) The odor of refrigerants does not prevent breathing; and D) Refrigerants do not contain acidic substances that would affect breathing.