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: Jennifer is climbing a mountain if and only if William is drinking water. Charles is not reading a book. If William drinks water, then Charles is reading a book. For all x_12, x_12 will play a game if and only if x_12 will climb a mountain.
William is not drinking water can be inferred via the modus tollens rule. If Jennifer climbs a mountain, then William is drinking water can be inferred via the biconditional elimination rule. If William drinks water, then Jennifer is climbing a mountain can be inferred via the biconditional elimination rule. For all x_12, if x_12 plays a game, then x_12 is climbing a mountain can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 climbs a mountain, then x_12 is playing a game can be inferred via the universal biconditional elimination rule.