Let $a$ and $b$ be non-zero real numbers such that $a \neq b$. Then the equation of the line passing through the origin and the point of intersection of $\frac{x}{a} + \frac{y}{b} = 1$ and $\frac{x}{b} + \frac{y}{a} = 1$ is :

Question

( A ) $bx + ay = 0$
( B ) $ax+by=0$
( C ) $x+y=0$
( D ) $y-x = 0$