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: There is at least one x_15 for which if x_15 were sad, then x_15 is sleeping. For all x_15, x_15 is a lawyer. For all x_15, x_15 will make tea if and only if x_15 will sleep. For all x_15, if x_15 were a lawyer, then x_15 is sad.
For all x_15, x_15 is sad can be inferred via the universal modus ponens rule. There is at least one x_15 for which if x_15 were a lawyer, then x_15 is sleeping can be inferred via the existential transitivity rule. For all x_15, if x_15 makes tea, then x_15 is sleeping can be inferred via the universal biconditional elimination rule. For all x_15, if x_15 sleeps, then x_15 is making tea can be inferred via the universal biconditional elimination rule.