Let $\mathrm{P}(\mathrm{a} \sec \theta, \mathrm{b} \tan \theta)$ and $\mathrm{Q}(\mathrm{a} \sec \phi, \mathrm{b} \tan \phi)$ where $\theta+\phi=\frac{\pi}{2}$ be two points on the hyperbola $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$. If $(h, k)$ is the point of intersection of the normals drawn at P and Q, then $\mathrm{k}=$

• A

  $\frac{a^2+b^2}{a}$
• Correct answer
  B

  $-\left(\frac{a^2+b^2}{b}\right)$
• C

  $-\left(\frac{a^2+b^2}{a}\right)$
• D

  $\frac{a^2+b^2}{b}$

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