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_16, x_16 will play tennis. For all x_16, x_16 is happy or x_16 is a scientist. For all x_16, if x_16 were happy, then x_16 is making tea. For all x_16, x_16 is sad if and only if x_16 will work. For all x_16, if x_16 makes tea, then x_16 is sad. For all x_16, x_16 will not work.
For all x_16, if x_16 were happy, then x_16 is sad can be inferred via the universal transitivity rule. For all x_16, if x_16 were sad, then x_16 is working can be inferred via the universal biconditional elimination rule. For all x_16, if x_16 works, then x_16 is sad can be inferred via the universal biconditional elimination rule. For all x_16, x_16 is not sad can be inferred via the universal biconditional elimination rule.