Multiply Using the Rule for Finding the Product of the Sum

Multiple Choice

Multiply using the rule for finding the product of the sum and difference of two terms.
- $$\left( 3 x + \frac { 1 } { 3 } \right) \left( 3 x - \frac { 1 } { 3 } \right)$$

A) $9 x ^ { 2 } - \frac { 2 } { 3 } x + \frac { 1 } { 9 }$
B) $9 x ^ { 2 } - \frac { 2 } { 3 }$
C) $9 x ^ { 2 } - \frac { 2 } { 3 } x - \frac { 1 } { 9 }$
D) $9 x ^ { 2 } - \frac { 1 } { 9 }$