Simplify the Radical Expression $\sqrt { 75 a ^ { 2 } b ^ { 3 } }$

Multiple Choice

Simplify the radical expression. All variables represent positive real numbers. $\sqrt { 75 a ^ { 2 } b ^ { 3 } }$

A) $3 a b \sqrt { 5 b }$
B) $5 a b \sqrt { 3 b }$
C) $3 a b + \sqrt { 5 b }$
D) $5 a b + \sqrt { 3 b }$
E) $5 + a b \sqrt { 3 b }$