A load of mass $m$ falls from a height $h$ on the scale pan hung from a spring as shown. If the spring constant is $k$ and the mass of the scale pan is zero and the mass $m$ does not bounce relative to the pan, then the amplitude of vibration is 

• A

  $\frac{mg}{k}$
• Correct answer
  B

  $\frac{mg}{k}\sqrt{1+\frac{2hk}{mg}}$
• C

  $\frac{mg}{k}+\frac{mg}{k}\sqrt{\frac{1+2hk}{mg}}$
• D

  None of these

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