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_8, if x_8 were a doctor, then x_8 is making tea. For all x_8, if x_8 makes tea, then x_8 is a doctor. Michael is not making tea. Michael is a doctor or it is cloudy.
For all x_8, x_8 is a doctor if and only if x_8 will make tea can be inferred via the universal biconditional introduction rule. For all x_8, x_8 will make tea if and only if x_8 is a doctor can be inferred via the universal biconditional introduction rule.