The angle between the lines joining the origin to the points of intersection of $x+2 y+1=0$ and $2 x^2-2 x y+3 y^2+2 x-y-1=0$ is

• A

  $\frac{\pi}{4}$
• B

  $\frac{\pi}{3}$
• Correct answer
  C

  $\frac{\pi}{2}$
• D

  $\frac{\pi}{6}$

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