Ice-water mass ratio is maintained as 1 : 1 in a given system containing water in equilibrium with ice at constant pressure. If $C_P\left(ice\right)=C_P\left(water\right)=4.18Jmo{l}^{-1}{K}^{-1}$ molar heat capacity of such a system is

The correct option is B Infinity
The molar heat capacity is the amount of heat required to increase the temperature of one mole of a substance by one degree.If some finite heat is supplied, the ice would melt to water, without any change in temperature. So the molar heat capacity = $\frac{Heatsupplied}{0}$ = Infinity.