Match each entropy expression to what it describes.

• $\Delta S = q_{rev}/T$ → The thermodynamic definition, via reversible heat
• $S = k \ln W$ → The statistical definition, via microstate counting
• $\Delta S_{universe} > 0$ → The condition for a process to be spontaneous
• $S = 0$ at 0 K → The absolute origin of the entropy scale

The first two are independent definitions that agree exactly; the third is the spontaneity criterion; the fourth is the third law, which makes absolute entropies tabulatable.