What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_4, if x_4 plays a game, then x_4 is not a nurse. For all x_4, x_4 is a nurse if and only if x_4 is a taxi driver. For all x_4, x_4 is a taxi driver.
For all x_4, if x_4 were a nurse, then x_4 is a taxi driver. For all x_4, if x_4 were a taxi driver, then x_4 is a nurse.