Multiply the Algebraic Expressions Using a Special Product Formula and Simplify

Multiple Choice

Multiply the algebraic expressions using a Special Product Formula and simplify. $( \sqrt { a } - b ) ( \sqrt { a } + b )$

A) $a ^ { 2 } + b ^ { 2 }$
B) $a - b ^ { 2 }$
C) $a + b ^ { 2 }$
D) $a - 2 a \sqrt { b } + b ^ { 2 }$
E) $a - 2 \sqrt { a b } - b ^ { 2 }$