The correct option is B 20 cal/∘C
Given,
Mass of aluminium (m)=100 g
Specific heat of aluminium (c)=0.2 cal/g∘C
Thermal capacity of material (S) = mass of material (m) × specific heat capacity of material (c)
Thus,
S=100×0.2=20 cal/∘C
Hence, option (b) is the correct answer.