What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: If Thomas were happy, then Patricia is not a mechanic. Patricia is not drinking water. Thomas is happy if and only if it is sunny. For all x_17, x_17 will drink water or x_17 is a mechanic.
If Thomas were happy, then it is sunny can be inferred via the biconditional elimination rule. If it is sunny, then Thomas is happy can be inferred via the biconditional elimination rule.