Which of the following statements are correct for rockets?
1. Unlike the turbo-jet aircraft, in rockets the flight velocity can exceed the jet velocity
2. In rockets gases having lower molecular weight increase the specific thrust
3. In rockets the gases are expanded in the nozzle up to the atmosphere pressure.
(A) 1, 2 and 3 (B) 1 and 2 only
(C) 2 and 3 only (D) 1 and 3 only