Final answer:
The compressor in an air conditioning system is responsible for converting low-pressure vapor into high-pressure vapor by compressing the refrigerant gas which then gets cycled through the system.
Step-by-step explanation:
When a system is operating, the compressor changes a low-pressure vapor to a high-pressure vapor. In an air conditioning system, the compressor plays a crucial role by taking in refrigerant gas at a low pressure and temperature and compressing it to a higher pressure and temperature. Once the vapor is compressed, it is then fed to the condenser, where it releases heat and turns back into a liquid form.
The air conditioning cycle continues as the high-pressure liquid passes through an expansion valve which reduces its pressure and temperature before entering the evaporator. Inside the evaporator, the refrigerant absorbs heat and turns into a low-pressure vapor again, restarting the cycle. The answer to the question is (a) Compressor.