When air to be compressed to reasonably high pressure, it is usually carried out by

Question

Consider the following statements:

When air to be compressed to reasonably high pressure, it is usually carried out by multi- stage compressor with an intercooler between the stages because

1. Work supplied is saved. 
2. Weight of compressor is reduced.
3. More uniform torque is obtained leading to the reduction in the size of flywheel.
4. Volumetric efficiency is increased.

Which of these statements is/are correct?

a) 1 alone                     b) 2 and 4

c) 1,2 and 3                 d) 1,2,3 and 4