Single stage impulse steam turbines are

Question

Assertion (A): Single stage impulse steam turbines are not used in practice.

Reason (R): Single stage impulse steam turbines have very low revolutions per minute                                       

Codes:

1.  Both A and R are individually true and R is the correct explanation of A
2. Bothe A and R are individually true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true