What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_2, if x_2 were an astronaut, then x_2 is rich. For all x_2, if x_2 were rich, then x_2 is an astronaut. For all x_2, if x_2 were an astronaut, then x_2 is rich.
For all x_2, x_2 is an astronaut if and only if x_2 is rich. For all x_2, x_2 is rich if and only if x_2 is an astronaut. For all x_2, x_2 is rich if and only if x_2 is an astronaut. For all x_2, x_2 is an astronaut if and only if x_2 is rich.