What does the term "R134a" refer to?

The term "R134a" refers to a type of refrigerant used in automotive air conditioning systems. This refrigerant is a hydrofluorocarbon (HFC) that has been widely adopted because it has a lower environmental impact compared to its predecessor, R-12, which is a chlorofluorocarbon (CFC) known to deplete the ozone layer. R134a is commonly utilized in both new vehicle air conditioning systems and in retrofitting older systems since it is non-toxic and non-flammable, making it safer for automotive use.

In contrast, the other options do not pertain to R134a: motor oils are distinct from refrigerants and have different classifications; tire pressure is measured in PSI and is unrelated to refrigerants; and engine coolant specifications refer to liquid substances used to manage engine temperature, which is also separate from refrigerant types. Thus, B captures the exact definition related to R134a within automotive systems.