Consider the following statements pertaining to specific speed of turbo machines:
1. Specific speed varies with shape of the runner and other parts of the machine.
2. Machines with highest specific speeds are limited to low heads.
3. Specific speed is dimensionless and 18 independent of variation of type of fluid used.
Which of the statements given above are correct?
a. 1, 2 and 3 b. 1 and 2 only
c. 2 and 3 only d. 1 and 3 only