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 z, if z makes tea, then z is listening to a song. For all z, z is a mechanic or z will make tea. For all z, z will read a book if and only if z is a mechanic. For all z, if z listens to a song, then z is reading a book.
For all z, if z makes tea, then z is reading a book can be inferred via the universal transitivity rule. For all z, if z reads a book, then z is a mechanic can be inferred via the universal biconditional elimination rule. For all z, if z were a mechanic, then z is reading a book can be inferred via the universal biconditional elimination rule.