Use the Properties of Logarithms to Rewrite the Expression $\log _ { 2 } ( 9 x + 9 y )$

Use the properties of logarithms to rewrite the expression. Simplify the result if possible. Assume all variables represent positive real numbers.
- $\log _ { 2 } ( 9 x + 9 y )$

A) $\log _ { 2 } 81 x y$
B) $\left( \log _ { 2 } 9 x \right) \left( \log _ { 2 } 9 y \right)$
C) $\log _ { 2 } ( 9 x + 9 y )$
D) $\log _ { 2 } 9 x + \log _ { 2 } 9 y$