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: Jessica is a writer. If Jessica were a writer, then Susan is listening to a song. David is an electrician if and only if Susan is listening to a song.
Susan is listening to a song can be inferred via the modus ponens rule. If David were an electrician, then Susan is listening to a song can be inferred via the biconditional elimination rule. If Susan listens to a song, then David is an electrician can be inferred via the biconditional elimination rule.