Find All Solutions to the Equation $\cos x = - \frac { 1 } { 2 }$

Multiple Choice

Find all solutions to the equation.
- $\cos x = - \frac { 1 } { 2 }$ (Express your answer in radians, in exact form.)

A) $\left\{ \frac { 5 \pi } { 6 } + \mathrm { n } \pi \quad \mathrm { |n } = 0 , \pm 1 , \pm 2 , \ldots . \cdot \right\}$
B) $\left\{ \frac { 2 \pi } { 3 } + 2 \mathrm { n } \pi , \frac { 4 \pi } { 3 } + 2 \mathrm { n } \pi \mid \mathrm { n } = 0 , \pm 1 , \pm 2 , \ldots \right\}$
C) $\left\{ \frac { 2 \pi } { 3 } + n \pi \quad \mid \mathrm { n } = 0 , \pm 1 , \pm 2 , \ldots \right\}$
D) $\left\{ \frac { 5 \pi } { 6 } + 2 \mathrm { n } \pi , \frac { 7 \pi } { 6 } + 2 \mathrm { n } \pi \mid \mathrm { n } = 0 , \pm 1 , \pm 2 , \ldots \right\}$