The correct option is B 2SO2(g)+O2(g)→2SO3(g)
Entropy is a measure of randomness of a system.
Entropy of gases is more than that of solids and liquids.
Entropy increases when there is increase in the number of moles (gaseous) on the product side, i.e., when △ng>0
For option (b),
2SO2(g)+O2(g)→2SO3(g)
△ng=2−3=−1
So, △S will be negative or entorpy decreases.