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, x_8 is a nurse or x_8 is not an office clerk. For all x_8, x_8 is an office clerk if and only if x_8 is happy.
For all x_8, if x_8 were an office clerk, then x_8 is a nurse can be inferred via the universal rewriting rule. For all x_8, if x_8 were an office clerk, then x_8 is happy can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were happy, then x_8 is an office clerk can be inferred via the universal biconditional elimination rule.