What is the equation to the straight line joining the origin to the point of intersection of the lines $\frac{x}{a}+\frac{y}{b}=1 \text { and } \frac{x}{b}+\frac{y}{a}=1 ?$

• A

  $x+y=0$
• B

  $x+y+1=0$
• Correct answer
  C

  $x-y=0$
• D

  $x+y+2=0$

Hence, the correct answer is option: 'C'.