The metallic bob of a simple pendulum has the relative density $\mathrm{\rho }$. The time period of this pendulum is T. If the metallic bob is immersed in water, then the new time period is

• A

  $\mathrm{T}\left(\frac{\mathrm{\rho }-1}{\mathrm{\rho }}\right)$

• B

  $\mathrm{T}\left(\frac{\mathrm{\rho }}{\mathrm{\rho }-1}\right)$

• C

  $\mathrm{T}\sqrt{\frac{\mathrm{\rho }-1}{\mathrm{\rho }}}$

• D

  $\mathrm{T}\sqrt{\frac{\mathrm{\rho }}{\mathrm{\rho }-1}}$