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 cook if and only if x_6 is a sailor. For all x_6, x_6 will cook or x_6 will not play tennis. For all x_6, x_6 will play tennis or x_6 is a sailor.
For all x_6, if x_6 plays tennis, then x_6 is cooking can be inferred via the universal rewriting rule. For all x_6, if x_6 cooks, then x_6 is a sailor can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 were a sailor, then x_6 is cooking can be inferred via the universal biconditional elimination rule.