Solve the System for X and Y Using Cramer's Rule $$\frac { 1 } { a } x + \frac { 1 } { b } y = a b$$

Solve the system for x and y using Cramer's rule. Assume a and b are nonzero constants.
- $$\frac { 1 } { a } x + \frac { 1 } { b } y = a b$$
$x + y = a$

A) $\left\{ \left\{ \frac { a ( b - a ) \left( b ^ { 2 } - 1 \right) } { a b ^ { 2 } } , \frac { ( b - a ) ( 1 - a b ) } { a b } \right) \right\}$

B) $\left\{ \left\{ \frac { a ^ { 2 } b \left( b ^ { 2 } - 1 \right) } { b - a } , \frac { a b ( 1 - a b ) } { b - a } \right) \right\}$

C) $\left\{ \left( \frac { a ^ { 2 } \left( b ^ { 2 } - 1 \right) } { b - a } , \frac { a b ( 1 - a b ) } { b - a } \right] \right\}$

D) $\left\{ \left( a b ( 1 - a b ) , a ^ { 2 } \left( b ^ { 2 } - 1 \right) \right) \right\}$