Find an Interval For $\theta$ For Which the Graph Is Traced Only Once

Multiple Choice

Find an interval for $\theta$ for which the graph is traced only once.
$$r = 2 \sin \left( \frac { 3 \theta } { 2 } \right)$$

A) $0 \leq \theta < \frac { \pi } { 3 }$
B) $0 \leq \theta < \pi$
C) $0 \leq \theta < 4 \pi$
D) $0 \leq \theta < \frac { 4 \pi } { 3 }$
E) $- 2 \pi \leq \theta < 2 \pi$