A particle of mass m is released from rest at point A falling parallel to vertical y-axis. Its angular momentum after falling through distance h about O is:

• A

  $\mathrm{ma}\sqrt{2\mathrm{gh}}$

• B

  $\frac{\mathrm{m}}{\mathrm{a}}\sqrt{2\mathrm{gh}}$

• C

  $\frac{\mathrm{ma}}{\mathrm{gh}}$

• D

  $\frac{\mathrm{mh}}{\mathrm{ag}}$