Write the Complex Number in Rectangular Form $4 \left( \cos 15 ^ { \circ } + i \sin 15 ^ { \circ } \right)$

Multiple Choice

Write the complex number in rectangular form.
- $4 \left( \cos 15 ^ { \circ } + i \sin 15 ^ { \circ } \right)$

A) $3.9 + 1 \mathrm { i }$
B) $1.9 + 0.5 \mathrm { i }$
C) $- 1.9 - 0.5 \mathrm { i }$
D) $1 + 3.9 \mathrm { i }$