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_5, if x_5 cooks, then x_5 is excited. For all x_5, if x_5 were excited, then x_5 is cooking. There is at least one x_5 for which if x_5 were excited, then x_5 is cooking.
For all x_5, x_5 will cook if and only if x_5 is excited can be inferred via the universal biconditional introduction rule. For all x_5, x_5 is excited if and only if x_5 will cook can be inferred via the universal biconditional introduction rule. There is at least one x_5 for which x_5 is excited if and only if x_5 will cook can be inferred via the existential biconditional introduction rule. There is at least one x_5 for which x_5 will cook if and only if x_5 is excited can be inferred via the existential biconditional introduction rule.