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: For all x_12, if x_12 works, then x_12 is a lawyer. There is at least one x_12 for which if x_12 works, then x_12 is not drinking water. For all x_12, x_12 will drink water. For all x_12, x_12 is a lawyer if and only if x_12 will work.
There is at least one x_12 for which x_12 will not work can be inferred via the existential modus tollens rule. For all x_12, if x_12 were a lawyer, then x_12 is working can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 works, then x_12 is a lawyer can be inferred via the universal biconditional elimination rule.