A string vibrates in its fundamental mode when a tension $T_1$ is applied to it. If the length of the string is decreased by $25 \%$ and the tension applied is changed to $\mathrm{T}_2$, the fundamental frequency of the string increases by $100 \%$, then $\frac{\mathrm{T}_2}{\mathrm{~T}_1}=$ (Linear density of the string is constant)

• A

  $\frac{3}{8}$
• B

  $\frac{2}{3}$
• C

  $\frac{8}{9}$
• Correct answer
  D

  $\frac{9}{4}$

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