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 Elisabeth writes a letter, then Elisabeth is cooking. Elisabeth is writing a letter if and only if it is windy. Elisabeth is not cooking. Patricia is driving a car.
Elisabeth is not writing a letter can be inferred via the modus tollens rule. Elisabeth is not cooking and Patricia is driving a car can be inferred via the conjunction rule. Patricia is driving a car and Elisabeth is not cooking can be inferred via the conjunction rule. If Elisabeth writes a letter, then it is windy can be inferred via the biconditional elimination rule. If it is windy, then Elisabeth is writing a letter can be inferred via the biconditional elimination rule.