Perform the Indicated Operations $( \sqrt { x } - 18 ) ^ { 2 }$

Multiple Choice

Perform the indicated operations. Assume that all variables represent positive numbers.
- $( \sqrt { x } - 18 ) ^ { 2 }$

A) $x - 36 \sqrt { x } + 324$
B) $x - 324$
C) $x + 324$
D) $x + 36 \sqrt { x } + 324$