If $x=\sec t+\tan t$ and $y=\sec t-\tan t$, where $t$ is a parameter, then the value of $\frac{dy}{dx}$ when $x=\frac{1}{\sqrt{3}}$ is

• A

  $0$
• Correct answer
  B

  $-3$
• C

  $\sqrt{3}$
• D

  $\frac{1}{\sqrt{3}}$

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