Multiply, and Then Simplify If Possible $( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$

Multiple Choice

Multiply, and then simplify if possible. Assume all variables represent positive real numbers.
- $( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$

A) $7 - 2 \sqrt { 5 }$
B) 2
C) 32
D) $- 18$