A given pendulum has a spherical solid bob of aluminium.Its period is I sec. Now this bob is replaced by a spherical solid bob of the same diameter but made of iron. Density of aluminium is 2.7 g/cc and that of iron is 9.8 g/cc. The period of oscillation of the pendulum will now be:

• A

  (26/9) sec

• B

  (9/27) sec

• C

  1 sec

• D

  2 sec