Find the Sum or Difference $$( 6 - 9 i ) + ( 3 + 6 i )$$

Multiple Choice

Find the sum or difference. Write the answer in standard form.
- $$( 6 - 9 i ) + ( 3 + 6 i )$$

A) $- 9 + 3 i$
B) $3 + 15 i$
C) $9 - 3 \mathrm { i }$
D) $9 + 3 \mathrm { i }$