The correct option is C △Ssystem decreases but △Ssurroundings increases.
Freezing of water is an exothermic process (heat releases).
As water freezes from liquid to solid, randomness (or entropy) decreases, i.e., △Ssystem decreases. Heat released during the process, is absorbed by the surroundings hence, △Ssurroundings increases.
Second Law of Thermodynamics:
It states that as energy is transferred or transformed, more and more of it is wasted. The Second Law also states that there is a natural tendency of any isolated system to degenerate into a more disordered state.
Note: Entropy of universe increases in the course of a spontaneous change.
ΔSuniv. is greater than 0
ΔSuniv.=ΔSsys+ΔSsurr > 0
For a spontaneous process in an isolated system, Entropy always increases
Also, When a system is in equilibrium, the entropy is maximum and the change in entropy, ΔS=0.