Just as internal energy U depends only on a system's current state, what does the source say about entropy S in this same respect?

1. Internal energy U is a property of a system's current state, fixed once pressure, volume and temperature are known, regardless of history. 2. The source draws a direct parallel for entropy, stating that entropy S, like internal energy U, depends only on the state of the system and not on how it reached that condition. 3. This is exactly why entropy for an irreversible process can be found by imagining any convenient reversible process between the same two states, which contradicts option C's claim that entropy is undefined outside reversible processes. 4. Both ΔS = Q/T and the statistical formula S = k ln W are usable ways to find entropy in the source, not just one of them exclusively, ruling out option D, and option A has the state-dependence backward. _Source: OpenStax College Physics (CC BY 4.0), Ch 15 "Thermodynamics", section 15.6 Entropy and the Second Law of Thermodynamics: Disorder and the Unavailability of Energy_