Answer: Option (c) is the correct answer.
Step-by-step explanation:
Entropy is defined as the degree of randomness. This means that more is the number of collisions taking place between atoms of a substance more will be the randomness.
Therefore, more will be the entropy of substance. We cannot measure the entropy but we can measure the change in entropy of a substance.
A thermometer is a glass tube that contains a liquid column generally mercury, and it is usually used to measure the temperature of human body.
A calorimeter is a device or apparatus that is used in a chemical reaction to measure the amount of heat involved.
Therefore, we can conclude that the student can't measure entropy directly, only an entropy change.