If the angle between the asymptotes of a hyperbola $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ is $2 \operatorname{Tan}^{-1}\left(\frac{2}{3}\right)$ and $\mathrm{a}^2-\mathrm{b}^2=45$, then $\mathrm{ab}=$

• A

  $20$
• B

  $24$
• C

  $45$
• Correct answer
  D

  $54$

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