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: Karen is excited. Michael is writing a letter. If Linda were an astronaut, then Karen is not excited.
Linda is not an astronaut can be inferred via the modus tollens rule. Karen is excited and Michael is writing a letter can be inferred via the conjunction rule. Michael is writing a letter and Karen is excited can be inferred via the conjunction rule.