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 y, if y were a mechanic, then y is drinking water. For all y, if y drinks water, then y is a mechanic. For all y, if y drinks water, then y is a mechanic.
For all y, y is a mechanic if and only if y will drink water can be inferred via the universal biconditional introduction rule. For all y, y is a mechanic if and only if y will drink water can be inferred via the universal biconditional introduction rule. For all y, y will drink water if and only if y is a mechanic can be inferred via the universal biconditional introduction rule. For all y, y will drink water if and only if y is a mechanic can be inferred via the universal biconditional introduction rule.