A block of mass 1 kg hangs without vibrating at the end of a spring whose force constant is 200 N/m and which is attached to the ceiling of an elevator. The elevator is rising with an upward acceleration of g/3 when the acceleration suddenly ceases. The angular frequency of the block after the acceleration ceases is

• A

  13 rad/s

• B

  14 rad/s 

• C

  15 rad/s

• D

  None of these