What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Barbara is playing tennis if and only if Barbara is playing squash. Mary is not running. Barbara is playing squash or it is sunny. Mary is running if and only if Barbara is playing tennis.
If Barbara plays tennis, then Barbara is playing squash. If Mary goes running, then Barbara is playing tennis. If Barbara plays squash, then Barbara is playing tennis. If Barbara plays tennis, then Mary is running. Barbara is not playing tennis.