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 y, if y were sad, then y is a scientist. If Jessica were a police officer, then Charles is sad. Charles is a scientist if and only if Jessica is a police officer.
If Charles were a scientist, then Jessica is a police officer can be inferred via the biconditional elimination rule. If Jessica were a police officer, then Charles is a scientist can be inferred via the biconditional elimination rule.