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: There is at least one x_8 for which x_8 is not a janitor. For all x_8, x_8 is curious if and only if x_8 is a janitor. For all x_8, x_8 is curious or x_8 is not a janitor.
For all x_8, if x_8 were a janitor, then x_8 is curious can be inferred via the universal rewriting rule. For all x_8, if x_8 were curious, then x_8 is a janitor can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a janitor, then x_8 is curious can be inferred via the universal biconditional elimination rule. There is at least one x_8 for which x_8 is not curious can be inferred via the existential biconditional elimination rule.