Find Sum of the Pair of Complex Numbers $- 6 i , 2 i$

Find sum of the pair of complex numbers.
- $- 6 i , 2 i$

A) $2 - 6 \mathrm { i }$
B) $- 4$
C) $- 6 + 2 i$
D) $- 4 \mathrm { i }$