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 x_14, if x_14 were an astronaut, then x_14 is playing a game. Joseph is writing a letter. For all x_14, x_14 will not play a game. For all x_14, x_14 is an astronaut or x_14 will make tea.
For all x_14, x_14 is not an astronaut can be inferred via the universal modus tollens rule.