Solve the System by the Method of Substitution $\left\{ \begin{aligned}\frac { 1 } { 5 } x + \frac { 1 } { 2 } y & = 8 \\x + y & = 21\end{aligned} \right.$

Multiple Choice

Solve the system by the method of substitution. $\left\{ \begin{aligned}\frac { 1 } { 5 } x + \frac { 1 } { 2 } y & = 8 \\x + y & = 21\end{aligned} \right.$

A) $\left( \frac { 25 } { 3 } , - \frac { 38 } { 3 } \right)$
B) (25, 38)
C) $\left( - \frac { 25 } { 3 } , \frac { 38 } { 3 } \right)$
D) $\left( \frac { 25 } { 3 } , \frac { 38 } { 3 } \right)$
E) (-25, -38)