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_6, x_6 will not drink water or x_6 will play tennis. For all x_6, x_6 will drink water or x_6 will cook. For all x_6, x_6 is poor if and only if x_6 will cook. There is at least one x_6 for which if x_6 plays tennis, then x_6 is poor.
For all x_6, x_6 will cook or x_6 will play tennis can be inferred via the universal resolution rule. For all x_6, if x_6 were poor, then x_6 is cooking can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 cooks, then x_6 is poor can be inferred via the universal biconditional elimination rule.