Three math students want to show that a proposition p is true iff (if and only if) q is true. In other words, they want to prove pq. Alice discovers a proof that shows pq. Bob discovers a proof that shows pq. Charlie discovers a proof that shows qp. (a) Can the three students together use what they found to prove pq ? Why or why not? (b) Are any of the proofs discovered redundant or unnecessary? Why or why not