A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be

Answer: Option D

The coefficient of performance or C.O.P. (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work required.
$$\text{C}\text{.O}\text{.P}\text{.}=\frac{120\text{kw}}{30\text{kw}}=4\text{kw}$$