If $\theta=\operatorname{Tan}^{-1}\left(\frac{1}{3}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{7}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{13}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{21}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{31}\right)$, then $\tan \theta=$

• A

  $\frac{3}{5}$
• B

  $1$
• Correct answer
  C

  $\frac{5}{7}$
• D

  $\frac{7}{9}$

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