Compressor capacity is highest, when the intake air temperature is
A. Highest
B. Lowest
C. Moderate
D. Zero

Hint:The volume of air delivered by the compressor is known as compressor capacity. The temperature of the air entering will be monitored by the intake air temperature. The intake air temperature is necessary to estimate air density so as to balance air and fuel mixture. Hot air is less dense than the cold air. Hence cold air requires more fuel to maintain the same air/fuel ratio.

Complete answer:
We know that the intake air temperature should be slightly higher than the atmospheric temperature when the compressor capacity is highest. Because the temperature of the air entering the compressor should be slightly higher than the atmospheric temperature to balance the air and fuel mixture which in turn increases the efficiency .We know that the temperature of the air entering is known as the intake temperature.Hence the intake temperature or the temperature of the air entering should be moderate.

Hence, option C is correct.

Note:Volumetric efficiency is one of the important parameters that determines the overall efficiency of the compressor. The volumetric efficiency is defined as the ratio of air available to the engine to its swept volume. In other words volumetric efficiency determines the mass of air that can be used to burn the fuel at any given operating point.