Evaluate the Polynomial Function $f ( x ) = x ^ { 2 } + 9 x + 4$

Multiple Choice

Evaluate the polynomial function.
-If $f ( x ) = x ^ { 2 } + 9 x + 4$ , find $f ( a )$

A) $a x ^ { 2 } + 9 a x + 4 a$
B) $10 a + 4$
C) $a ^ { 2 } + 9 a + 4$
D) $a ^ { 2 } + 13 a$