Multiply, and Then Simplify If Possible $( \sqrt { 5 } + \sqrt { 11 } ) ( \sqrt { 5 } - \sqrt { 11 } )$

Multiple Choice

Multiply, and then simplify if possible. Assume all variables represent positive real numbers.
- $( \sqrt { 5 } + \sqrt { 11 } ) ( \sqrt { 5 } - \sqrt { 11 } )$

A) $- 6$
B) $5 - 2 \sqrt { 5 }$
C) $5 - 2 \sqrt { 11 }$
D) 16