Let $f ( x ) = \ln ( \cos x )$

Multiple Choice

Let $f ( x ) = \ln ( \cos x )$ Then $f ^ { \prime } ( x )$ is

A) $- \sin x \cos x$
B) $- \frac { 1 } { \sin x \cos x }$
C) -tan x
D) -cot x
E) -csc x