What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Barbara cooks, then Charles is curious. If Barbara cooks, then Robert is a lawyer. If Robert were a lawyer, then Barbara is cooking. If Charles were curious, then Robert is a lawyer.
If Barbara cooks, then Robert is a lawyer. If Robert were a lawyer, then Charles is curious. If Charles were curious, then Barbara is cooking. Barbara is cooking if and only if Robert is a lawyer. Robert is a lawyer if and only if Barbara is cooking.