Perform the Indicated Operation $( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$

Multiple Choice

Perform the indicated operation. Assume that all variables represent positive real numbers.
- $( \sqrt { 7 } + 5 ) ( \sqrt { 7 } - 5 )$

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