A cubical block of wood of edge a and density rho floats in water of density 2. The lower surface of the cube just touches the free end of a mass less spring of force constant K fixed at the bottom of the vessel. The weight W put over the block so that it is completely immersed in water without wetting the weight is:
A. a(a²rhog+k)
B. a(arhog+2k)
C. a(arhog/2+2k)
D. a(a2rhog+k/2)