Answer:
B: Greatest, A: Second greatest, C: Second geratest.
Step-by-step explanation:
We can calculate the heat of fusion of a material (ΔHfus), which is the heat required to melt 1 kg of material, using the following expression.
ΔHfus = Q/m
where,
Material A
ΔHfus = 200 J/4 kg = 50 J/kg
Material B
ΔHfus = 300 J/5 kg = 60 J/kg
Material C
ΔHfus = 300 J/6 kg = 50 J/kg
Then, considering the heats of fusion,
B: Greatest, A: Second greatest, C: Second greatest.