The volumetric efficiency of a compressor depends upon

Question

Consider the following statements:

The volumetric efficiency of a compressor depends upon       

1. Clearance volume.
2. Pressure ratio.
3. Index of expansion.

Which of these statements are correct?

       (a) 1 and 2            (b) 1 and 3

        (c) 2 and 3             (d) 1,2 and 3