A cubical block of copper of side 10 cm is floating in a vessel containing mercury. Water is poured into the vessel so that the copper block just gets submerged. The height of water column is

(${\mathrm{\rho }}_{\mathrm{Hg}} = 13.6 \mathrm{g}/\mathrm{cc}, {\mathrm{\rho }}_{\mathrm{Cu}} = 7.3\mathrm{g}/\mathrm{cc}, {\mathrm{\rho }}_{\mathrm{water}} = 1 \mathrm{gm}/\mathrm{cc}$)

• A

  1.25 cm

• B

  2.5 cm

• C

  5 cm

• D

  7.5 cm