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_7, x_7 is a musician if and only if x_7 is an electrician. For all x_7, x_7 is a musician or x_7 is not a police officer.
For all x_7, if x_7 were a police officer, then x_7 is a musician can be inferred via the universal rewriting rule. For all x_7, if x_7 were a musician, then x_7 is an electrician can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were an electrician, then x_7 is a musician can be inferred via the universal biconditional elimination rule.