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: Jennifer is not an astronaut. If Joseph plays squash, then Sarah is making tea. Sarah is making tea if and only if Jennifer is an astronaut. Joseph is playing squash or Sarah is not making tea.
If Sarah makes tea, then Joseph is playing squash can be inferred via the rewriting rule. If Sarah makes tea, then Jennifer is an astronaut can be inferred via the biconditional elimination rule. If Jennifer were an astronaut, then Sarah is making tea can be inferred via the biconditional elimination rule. Sarah is not making tea can be inferred via the biconditional elimination rule.