The amount of heat required to melt a substance at its melting point is given by
[tex]Q=m L_f[/tex]
where m is the mass of the substance and Lf is its latent heat of fusion. During the phase change, the temperature of the substance does not change, and all the energy given to the substance is used to break the bonds between the molecules. In this problem, we have a block of ice of mass m=0.3 kg. The specific latent heat of ice is 334 kJ/kg: therefore, the amount of heat required to melt it is given by
[tex]Q=mL_f =(0.3 kg)(334 kJ/kg)=100.3 kJ [/tex]
So, the correct answer is A) 100375 J
