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_16, x_16 is a lawyer or x_16 will play tennis. For all x_16, x_16 is sad or x_16 is a doctor. For all x_16, if x_16 were a doctor, then x_16 is a cashier. For all x_16, x_16 is a cashier or x_16 is not sad. For all x_16, if x_16 were a lawyer, then x_16 is listening to a song. There is at least one x_16 for which if x_16 plays tennis, then x_16 is listening to a song.
For all x_16, if x_16 were sad, then x_16 is a cashier can be inferred via the universal rewriting rule. There is at least one x_16 for which x_16 will listen to a song can be inferred via the existential disjunction elimination rule.