What Is the Equation of the Normal Line to the Graph

Multiple Choice

What is the equation of the normal line to the graph of $f ( x ) = 3 \sqrt { x } + 2$ at $x = 9$ ?

A) $y = - 2 x$
B) $y - 11 = - 2 ( x - 9 )$
C) $y - 11 = 0.5 ( x - 9 )$
D) $y = 0.5 x$
E) $y = 0.5 x - 9$