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: There is at least one x_8 for which x_8 will play tennis or x_8 is sad. For all x_8, x_8 will not play tennis. For all x_8, x_8 will read a book and x_8 is a nurse.
There is at least one x_8 for which x_8 is sad can be inferred via the existential disjunctive syllogism rule. For all x_8, x_8 will read a book can be inferred via the universal simplification rule. For all x_8, x_8 is a nurse can be inferred via the universal simplification rule.