A Block of Wood of Mass 400 G and Density

Multiple Choice

A block of wood of mass 400 g and density 0.8 g/cm³ is floating on the surface of a liquid of density 1.3 g/cm³.What is the difference in mass of stone (density = 1.9 g/cm³) that must be added to the block in order for the combination (wood and stone) to be just submerged rather than only the wood to be submerged?

A) 250 g
B) 540 g
C) 170 g
D) 790 g
E) none of the above