Hydrofluorocarbons (HFCs) are commonly used in diverse applications due to their properties. Let`s dissect each option:

Option 1: Aerosols. HFCs are used as propellants in aerosols as they are safer for the ozone layer compared to alternatives.

Option 2: Foam agents. They are used in the production of foams due to their abilities to produce a light, strong structure.

Option 3: Fire retardants. HFCs are used in fire extinguishing systems, they are non-conductive and do not leave any residue.

Option 4: Lubricants. HFCs aren`t typical ingredients in lubricants but are used in specialized applications where chemical stability and non-flammability are required.

Although their use may be less prevalent in lubricants, they are still used, making Option 4, "All four," the correct answer. It`s important to keep in mind that HFC use is being phased out due to their high global warming potential.