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_4, if x_4 drinks water, then x_4 is a lawyer. For all x_4, if x_4 sleeps, then x_4 is working. There is at least one x_4 for which x_4 will sleep. For all x_4, if x_4 works, then x_4 is a lawyer.
There is at least one x_4 for which x_4 will work can be inferred via the existential modus ponens rule. For all x_4, if x_4 sleeps, then x_4 is a lawyer can be inferred via the universal transitivity rule.