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 is sad or x_12 will go running. There is at least one x_12 for which if x_12 were sad, then x_12 is not a musician. For all x_12, x_12 is a musician.
There is at least one x_12 for which x_12 is not sad can be inferred via the existential modus tollens rule.