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_14, x_14 is not a musician. If David were rich, then Michael is a lawyer. Michael is a lawyer if and only if Susan is a musician.
If Michael were a lawyer, then Susan is a musician can be inferred via the biconditional elimination rule. If Susan were a musician, then Michael is a lawyer can be inferred via the biconditional elimination rule.