The correct option is B I and II only
The reactions I and II only represent the decrease in entropy.
In reaction I, a gas is condensed into liquid. In reaction II, two hydrated ions (cation and anion) combine to form a solid. As we move from gas to liquid or liquid to gas, the entropy decreases.
The reaction III represent the increase in entropy.
In reaction II, 2 moles of gaseous reactants give 3 moles of gaseous products. With increase in the number of moles of gaseous species, the entropy increases.