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: Barbara is drinking water if and only if James is a mechanic. James is not a mechanic.
If Barbara drinks water, then James is a mechanic can be inferred via the biconditional elimination rule. If James were a mechanic, then Barbara is drinking water can be inferred via the biconditional elimination rule. Barbara is not drinking water can be inferred via the biconditional elimination rule.