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 William were a server, then Elisabeth is reading a book. For all x_14, if x_14 were sad, then x_14 is reading a book. William is a server or Elisabeth is sad. If it is late, then Elisabeth is not reading a book.
If Elisabeth plays tennis, then William is a server can be inferred via the rewriting rule.