What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, x_12 is not sad. For all x_12, if x_12 were a bartender, then x_12 is not climbing a mountain. For all x_12, if x_12 sleeps, then x_12 is an electrician. For all x_12, x_12 will sleep or x_12 will climb a mountain. For all x_12, x_12 is an electrician if and only if x_12 is sad.
For all x_12, if x_12 were an electrician, then x_12 is sad. For all x_12, if x_12 were sad, then x_12 is an electrician. For all x_12, x_12 is not an electrician.