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: t <-> q. ~r_2. r_2 or t.
t can be inferred via the disjunctive syllogism rule. t -> q can be inferred via the biconditional elimination rule. q -> t can be inferred via the biconditional elimination rule.