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

Multiple Choice

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

A) $10 \sqrt { 5 }$
B) $\sqrt { 15 } + \sqrt { 35 }$
C) $5 \sqrt { 3 } + 5 \sqrt { 7 }$
D) $\sqrt { 50 }$