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 takes a plane, then y is driving a car. For all y, y will write a letter and y is a taxi driver. For all y, y will take a plane or y will not write a letter.
For all y, y will write a letter can be inferred via the universal simplification rule. For all y, y is a taxi driver can be inferred via the universal simplification rule. For all y, if y writes a letter, then y is taking a plane can be inferred via the universal rewriting rule.