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, if x_8 were an astronaut, then x_8 is drinking water. For all x_8, x_8 will drink water if and only if x_8 is an astronaut. For all x_8, if x_8 drinks water, then x_8 is a nurse.
For all x_8, if x_8 were an astronaut, then x_8 is a nurse can be inferred via the universal transitivity rule. For all x_8, if x_8 drinks water, then x_8 is an astronaut can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were an astronaut, then x_8 is drinking water can be inferred via the universal biconditional elimination rule.