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_11, if x_11 makes tea, then x_11 is writing a letter. For all x_11, if x_11 writes a letter, then x_11 is playing squash. For all x_11, x_11 is rich if and only if x_11 will play squash. For all x_11, if x_11 were an office clerk, then x_11 is making tea. For all x_11, x_11 is not rich.
For all x_11, if x_11 makes tea, then x_11 is playing squash can be inferred via the universal transitivity rule. For all x_11, if x_11 were an office clerk, then x_11 is writing a letter can be inferred via the universal transitivity rule. For all x_11, if x_11 were rich, then x_11 is playing squash can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 plays squash, then x_11 is rich can be inferred via the universal biconditional elimination rule. For all x_11, x_11 will not play squash can be inferred via the universal biconditional elimination rule.