$$\text { Evaluate (if possible) the function } f ( x ) = \sqrt { x - 5 } \text { at } x = 9 \text {. Simplify the result. }$$

Multiple Choice

$$\text { Evaluate (if possible) the function } f ( x ) = \sqrt { x - 5 } \text { at } x = 9 \text {. Simplify the result. }$$

A) 3
B) 2
C) $- 2$
D) 4
E) undefined