Which of the following statements correctly summarizes the zeroth law of thermodynamics?

W) If each of two systems are in thermal equilibrium with a third system, they must be in thermal equilibrium with each other

X) When energy passes as work, heat, or with matter, into or out of a system, its internal energy changes in accord with the law of conservation of energy

Y) In a natural thermodynamic process, the sum of the entropies of the participating thermodynamic systems increases

Z) The entropy of a system approaches a constant value as the temperature approaches absolute zero
W) IF EACH OF TWO SYSTEMS ARE IN THERMAL EQUILIBRIUM WITH A THIRD SYSTEM, THEY MUST BE IN THERMAL EQUILIBRIUM WITH EACH OTHER