Simplify the Radical Expression $( \sqrt { 8 } + 3 ) ( \sqrt { 8 } - 3 )$

Multiple Choice

Simplify the radical expression. Assume all variables represent positive real numbers.
- $( \sqrt { 8 } + 3 ) ( \sqrt { 8 } - 3 )$

A) $- 1$
B) $8 - 2 \sqrt { 3 }$
C) 17
D) 5