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: p_12 <-> q_17. t <-> q_17. t or p_12.
p_12 -> q_17 can be inferred via the biconditional elimination rule. t -> q_17 can be inferred via the biconditional elimination rule. q_17 -> p_12 can be inferred via the biconditional elimination rule. q_17 -> t can be inferred via the biconditional elimination rule.