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: It is sunny or David is running. James is not sleeping. For all x_11, x_11 will sleep if and only if x_11 is an astronaut. It is not sunny.
David is running can be inferred via the disjunctive syllogism rule. James is not sleeping and it is not sunny can be inferred via the conjunction rule. It is not sunny and James is not sleeping can be inferred via the conjunction rule. For all x_11, if x_11 sleeps, then x_11 is an astronaut can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 were an astronaut, then x_11 is sleeping can be inferred via the universal biconditional elimination rule.