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: Charles is drinking water or Karen is rich. Charles is not drinking water. Elisabeth is not playing tennis. For all x_11, x_11 will play tennis if and only if x_11 is a server.
Karen is rich can be inferred via the disjunctive syllogism rule. Charles is not drinking water and Elisabeth is not playing tennis can be inferred via the conjunction rule. Elisabeth is not playing tennis and Charles is not drinking water can be inferred via the conjunction rule. For all x_11, if x_11 plays tennis, then x_11 is a server can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 were a server, then x_11 is playing tennis can be inferred via the universal biconditional elimination rule.