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 Patricia drinks water, then Barbara is not driving a car. For all x_1, if x_1 reads a book, then x_1 is drinking water. If Charles plays squash, then Patricia is reading a book. Barbara is driving a car.
Patricia is not drinking water can be inferred via the modus tollens rule.