Solve the Problem $y = \cos x , 0 \leq x \leq 2 \pi$

Multiple Choice

Solve the problem.
-Find all points on the curve $y = \cos x , 0 \leq x \leq 2 \pi$ , where the tangent line is parallel to the line $y = - x$ .

A) $\left( \frac { \pi } { 2 } , 0 \right)$
B) $\left( \frac { 3 \pi } { 2 } , 0 \right)$
C) $( 2 \pi , 1 )$
D) $( \pi , - 1 )$