An object's heat capacity is defined to be
a. the amount of heat energy needed to raise its temperature by 1°c
b. the ratio of its specific heat to that of water
c. its ability to quickly heat up and glow red-hot
d. the amount of heat energy per kilogram needed to raise its temperature by 1°c
e. the change in its temperature caused by adding 1 j of heat
f. the amount of heat energy needed to change its state without changing its temperature