At the mould exit of a continuous caster, the metal consisting of a solidified shell with a liquid metal core exits at the rate of 35 kg S-1. Given that the latent heat of fusion is 3 × 105 J kg-1 and the total rate of heat removal by the mould is 4.2 × 106 W, the mass fraction of solid at the mould exit is . . . . . . . . Assume that both while solid and liquid remain at the melting point, they are in the mould.

Answer: Option B