A cubical block of steel each side 'l' is floating in mercury in a vessel.The densities of steel and mercury are pₛ and pₘ. The height of block above the mercury level is given by

a. l(1+pₛ/pₛ)
b. l(1-pₛ/pₘ)
c. l(1+pₘ/pₛ)
d. l(1-pₘ/pₛ)