Perform the Indicated Operation and Simplify $a + bi$ - $\sqrt { - 81 }$

Multiple Choice

Perform the indicated operation and simplify. Write the result in the form a $a + bi$
- $\sqrt { - 81 }$

A) $0 + 9 \mathrm { i }$
B) $9 + 0 \mathrm { i }$
C) $0 - 9 \mathrm { i }$
D) $0 - \mathrm { i } \sqrt { 9 }$