Evaluate the Double Integral Over the Given Region $$\iint _ { R } ( \sqrt { x } + \sqrt { y } ) d A , \quad R : 0 \leq x \leq 1,0 \leq y \leq 1$$

Multiple Choice

Evaluate the double integral over the given region.
- $$\iint _ { R } ( \sqrt { x } + \sqrt { y } ) d A , \quad R : 0 \leq x \leq 1,0 \leq y \leq 1$$

A) $\frac { 2 } { 3 }$
B) $\frac { 4 } { 3 }$
C) $\frac { 8 } { 3 }$
D) $\frac { 1 } { 3 }$