Choked flow through a nozzle means:

Question

Consider the following statements:

Choked flow through a nozzle means:

1. Discharge is maximum
2. Discharge is zero      
3. Velocity at throat is supersonic
4. Nozzle exit pressure is less than or equal to critical pressure.

Which of these statements is/are correct?

(a) 1 only                     (b) 1 and 2      

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