Write the Complex Number in Rectangular Form $\operatorname { cis } 210$

Multiple Choice

Write the complex number in rectangular form.
- $\operatorname { cis } 210$

A) $- \frac { \sqrt { 3 } } { 2 } - \frac { 1 } { 2 } \mathrm { i }$
B) $\frac { \sqrt { 3 } } { 2 } - \frac { 1 } { 2 } \mathrm { i }$
C) $- \frac { 1 } { 2 } + \frac { - 1 } { 2 } \mathrm { i }$
D) $- \frac { \sqrt { 3 } } { 2 } + \frac { 1 } { 2 } \mathrm { i }$