Multiply, and Then Simplify If Possible $\sqrt { 7 } ( \sqrt { 5 } + \sqrt { 3 } )$

Multiple Choice

Multiply, and then simplify if possible. Assume all variables represent positive real numbers.
- $\sqrt { 7 } ( \sqrt { 5 } + \sqrt { 3 } )$

A) $8 \sqrt { 7 }$
B) $\sqrt { 56 }$
C) $7 \sqrt { 5 } + 7 \sqrt { 3 }$
D) $\sqrt { 35 } + \sqrt { 21 }$