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 z_4, if z_4 were a poet, then z_4 is a lawyer. For all z_4, z_4 will drink water if and only if z_4 is a lawyer. There is at least one z_4 for which if z_4 drinks water, then z_4 is a poet.
There is at least one z_4 for which if z_4 drinks water, then z_4 is a lawyer can be inferred via the existential transitivity rule. For all z_4, if z_4 drinks water, then z_4 is a lawyer can be inferred via the universal biconditional elimination rule. For all z_4, if z_4 were a lawyer, then z_4 is drinking water can be inferred via the universal biconditional elimination rule.