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: If David listens to a song, then Sarah is a politician. If Richard were a police officer, then it is overcast. David is listening to a song. Sarah is a politician if and only if Richard is a police officer.
Sarah is a politician can be inferred via the modus ponens rule. If Sarah were a politician, then Richard is a police officer can be inferred via the biconditional elimination rule. If Richard were a police officer, then Sarah is a politician can be inferred via the biconditional elimination rule.