Answer: Option (a) is the correct answer.
Explanation:
Entropy is defined as the degree of randomness present in a substance. This means that more randomly the atoms in a substance are moving more will be entropy of the substance.
Entropy of a substance increases with increase in temperature.
For example, when a piece of wood is burned then its molecules will gain kinetic energy and hence, they start to move randomly from one place to another.
As a result, there will occur an increase in its entropy.
Thus, we can conclude that when a piece of wood is burned then its entropy increases.