Find the Domain of the Function $$f ( x ) = \sqrt { 9 - x }$$

Find the domain of the function.
- $$f ( x ) = \sqrt { 9 - x }$$

A) $\{ x \mid x \neq 9 \}$
B) {x|x ≤9}
C) {x|x ≤3}
D) {x|x ≠3}