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_5, if x_5 were curious, then x_5 is a sailor. For all x_5, if x_5 were a sailor, then x_5 is curious. For all x_5, x_5 is not a sailor. For all x_5, x_5 is curious or x_5 will drink water.
For all x_5, x_5 is not curious can be inferred via the universal modus tollens rule. For all x_5, x_5 is curious if and only if x_5 is a sailor can be inferred via the universal biconditional introduction rule. For all x_5, x_5 is a sailor if and only if x_5 is curious can be inferred via the universal biconditional introduction rule.