Text: If the RWC is &lt;25% effluent the concentrations may  (1) 4 times the RWC, (2) 2 times the RWC, (3) RWC, (4) RWC/2, and (5) RWC/4.
Entailment: If the RWC is under 25%, the concentrations vary.
Contradiction: Even if the RWC is under 25%, the concentrations do vary.