Simplify the Expression $$\sqrt { \frac { 2 } { 3 } } - \sqrt { \frac { 72 } { 108 } }$$

Multiple Choice

Simplify the expression. Assume all variables represent positive real numbers.
- $$\sqrt { \frac { 2 } { 3 } } - \sqrt { \frac { 72 } { 108 } }$$

A) 0
B) $- 1$
C) $- 6$
D) $- \frac { 1 } { 6 }$