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 Sarah were an office clerk, then it is cloudy. If Sarah were an office clerk, then it is cloudy. If it is cloudy, then Sarah is an office clerk.
Sarah is an office clerk if and only if it is cloudy can be inferred via the biconditional introduction rule. Sarah is an office clerk if and only if it is cloudy can be inferred via the biconditional introduction rule. It is cloudy if and only if Sarah is an office clerk can be inferred via the biconditional introduction rule. It is cloudy if and only if Sarah is an office clerk can be inferred via the biconditional introduction rule.