Find the Function Value Indicated for the Function $f ( x ) = \sqrt { x - 25 }$

Multiple Choice

Find the function value indicated for the function. If necessary, round to two decimal places. If the function value is not a real number and does not exist, state so.
-Evaluate $f ( x ) = \sqrt { x - 25 }$ for $f ( 1 )$

A) $- \sqrt { 24 }$
B) not a real number
C) 24
D) $- 4$