Consider the following statements regarding the specific speeds of a centrifugal pump:
1. Specific speed is defined as the speed of a geometrically similar pump developing unit power under unit head.
2. At the same specific speed, the efficiency is greater with larger capacity.
3. The specific speed increases with increases in outer blade angle.
4. The specific speed varies directly as the square root of the pump discharge.
Which of these statements are correct?
(a) 1 and 2 (b) 2 and 4
(c) 3 and 4 (d) 2 and 3