The volumetric efficiency of a reciprocating compressor can be enhanced by

Question

Consider the following statements:

The volumetric efficiency of a reciprocating compressor can be enhanced by                                               

1. Heating the intake air.
2. Decreasing the clearance volume.
3. Cooling the intake air

Which of these statements is/are correct?

(a) 1 alone             (b) 1 and 2

(c) 2 and 3             (d) 3 alone