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_12, x_12 will write a letter. For all x_12, if x_12 listens to a song, then x_12 is reading a book. There is at least one x_12 for which if x_12 makes tea, then x_12 is not writing a letter. For all x_12, x_12 will make tea or x_12 will listen to a song.
There is at least one x_12 for which x_12 will not make tea can be inferred via the existential modus tollens rule.