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 reads a book, then y is a nurse. For all y, if y were a nurse, then y is writing a letter. For all y, y will read a book or y is not a nurse. For all y, y will not write a letter.
For all y, y is not a nurse can be inferred via the universal modus tollens rule. For all y, if y reads a book, then y is writing a letter can be inferred via the universal transitivity rule. For all y, if y were a nurse, then y is reading a book can be inferred via the universal rewriting rule.