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

Multiple Choice

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

A) $\left\{ \left( b + a , - \frac { 1 } { a b } \right\} \right\}$
B) $\left\{ \left( \frac { 1 } { a b } , \frac { a - b } { a b } \right\} \right\}$
C) $\left\{ \left( \frac { a + b } { a b } , - \frac { 1 } { a b } \right) \right\}$
D) $\left\{ \left( \frac { b - a } { a b } , - \frac { 1 } { a b } \right) \right\}$