Find All Solutions to the Equation in the Interval [0 $\cos x - \cos 3 x = 0$

Multiple Choice

Find all solutions to the equation in the interval [0, 2) .
- $\cos x - \cos 3 x = 0$

A) $0 , \frac { \pi } { 2 } , \frac { 3 \pi } { 2 }$
B) 0
C) $\frac { \pi } { 2 } , \frac { 3 \pi } { 2 }$
D) $0 , \frac { \pi } { 2 } , \pi , \frac { 3 \pi } { 2 }$