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_8, x_8 is a server if and only if x_8 is poor. For all x_8, x_8 is not a server. For all x_8, x_8 will not listen to a song or x_8 is poor. For all x_8, x_8 will not drink water or x_8 will cook. For all x_8, x_8 will listen to a song or x_8 will drink water.
For all x_8, x_8 will drink water or x_8 is poor can be inferred via the universal resolution rule. For all x_8, if x_8 were a server, then x_8 is poor can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were poor, then x_8 is a server can be inferred via the universal biconditional elimination rule. For all x_8, x_8 is not poor can be inferred via the universal biconditional elimination rule.