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_13, if x_13 were an astronaut, then x_13 is a nurse. For all x_13, x_13 is a soldier or x_13 is an astronaut. For all x_13, if x_13 were a soldier, then x_13 is a nurse.
For all x_13, x_13 is a nurse can be inferred via the universal disjunction elimination rule.