A whistle producing sound waves of frequencies $9500 \mathrm{~Hz}$ and above is approaching a stationary person with speed $v \mathrm{~ms}^{-1}$. The velocity of sound in air is $300 \mathrm{~ms}^{-1}$. If the person can hear frequencies upto a maximum of $10,000 \mathrm{~Hz}$, the maximum value of $\mathrm{v}$ upto which he can hear the whistle is

• A

  $30 \mathrm{~ms}^{-1}$
• B

  $15 \sqrt{2} \mathrm{~ms}^{-1}$
• C

  $15 / \sqrt{2} \mathrm{~ms}^{-1}$
• Correct answer
  D

  $15 \mathrm{~ms}^{-1}$

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