Simplify the Algebraic Expression by Combining Similar Terms $\frac { 2 } { 7 } x + \frac { 1 } { 4 } y + \frac { 1 } { 3 } x + \frac { 7 } { 8 } y$

Multiple Choice

Simplify the algebraic expression by combining similar terms. $\frac { 2 } { 7 } x + \frac { 1 } { 4 } y + \frac { 1 } { 3 } x + \frac { 7 } { 8 } y$

A) $\frac { 9 } { 8 } x + \frac { 13 } { 21 } y$
B) $\frac { 13 } { 21 } x + \frac { 8 } { 9 } y$
C) $\frac { 23 } { 21 } x y$
D) $\frac { 13 } { 21 } x + \frac { 9 } { 8 } y$
E) $\frac { 21 } { 23 } ( x + y )$