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: Karen is not writing a letter. Karen is not a cashier or Patricia is playing a game. Karen is not a lawyer or Karen is writing a letter. For all x_9, x_9 is a lawyer or x_9 is a cashier.
Nothing can be inferred from these premises.