Electric motor

Engine

Either (A) or (B)

None of the above

Roots blower compressor

Centrifugal blower compressor

Axial flow compressor

Both (B) and (C)

Centrifugal type

Axial flow type

Radial flow type

None of these

Small quantities of air at high pressures

Large quantities of air at high pressure

Small quantities of air at low pressure

Large quantities of air at low pressure

No propeller

Propeller in front

Propeller at back

Propeller on the top