Question about sippur Yosef

Aviva Novick asks:
1) Going back a few parshiot... I still don't understand why Yosef put his brothers through the whole episode when he claims that they're spies and makes them bring down Binyamin.
i've heard 3 possible answers, none of which I like, or maybe I just dont fully understand them:
a) "Yosef was tyring to make his dreams come true." I see where they're getting this from in the text, but why would yosef have to make his dreams come true? its not a navi's job to make his nevuot come true. why is this different?
b) "He wanted to see if the brothers had changed their ways and improved." why? for personal satisfaction? Its up to them to change, why does he need proof?
c) "Yosef wanted to provide the brothers with a chance to do Teshuva in olam haZeh so that their punishment wouldn't be so harsh in olam haBa." Why is it Yosef's place to do this? Hashem will give out reward and punishment as He sees fit. If Hashem wanted to give them an identical situation to michirat yosef so that they could do teshuva, Hashem would do it. It doesn't seem right for Yosef to step in.

The way I like to think about the Yosef story is along the lines of your answer b), that Yosef accused his brothers of being spies and asked them to bring him Binyamin in order to see if they had changed their ways and improved. The reason he did so was not to satisfy his own curiosity, but because the question of whether his brothers had done teshuva would determine the correct course of action for him to take. When Yosef saw his brothers coming to Mitzrayim for food, he probably wanted to tell them who he was immediately so he could reunite with Yaakov, whom he had missed for so many years. However, if the brothers still hated him, this would be an unwise idea that would just cause more problems for the family and stir up trouble in the waning years of Yaakov’s life. Moreover, the fact that the brothers came without Binyamin might have indicated to Yosef that there were indeed still problems between Bnei Leah and Bnei Rachel—otherwise, why wouldn’t he be with the rest of his brothers? Maybe they were estranged from him too! In fact, Rav Yoel Bin-Nun suggests that Yosef may have even thought that Yaakov himself had rejected him. Yosef knew that Avraham and Yitzchak had each had one son whom they loved and another son whom they rejected. He knew that, back in perek 37, Yaakov had sent him on a long journey alone to find his brothers, and when he found them, they immediately threw him into a pit and sold him into slavery! Therefore, he may have actually thought that Yaakov had been complicit with the brothers in the plan to sell him. Since he didn’t know if the brothers still hated him or even if Yaakov had rejected him, and since Binyamin’s absence might have made him think that the Bnei Rachel really had been rejected by the family, he honestly didn’t know what to do next when he saw his brothers. He may have wanted to reveal his identity, but may not have known if this would cause more problems than it would solve.
In order to figure out whether it was safe or wise for him to reveal who he was, Yosef asked the brothers to bring him Binyamin. If they couldn’t produce Binyamin, that would be another indication that they had really rejected Binyamin also—maybe they had sold him into slavery too! When they did bring Binyamin, Yosef still didn’t know if they felt loyalty to Binyamin (and, by extension, to him) or whether they hated Binyamin the same way they had hated him. He arranged a situation in which the brothers were forced to decide whether to sell Binyamin into slavery as they had sold Yosef into slavery, in order to protect themselves. If they had decided to leave Binyamin in Mitzrayim as Yosef’s slave, Yosef would have known that it was not possible for him to reconcile with his family. When they left, he probably would have revealed his identity to Binyamin and treated him well, allowing him a good life as opposed to the life he would have endured with his brothers who hated him. However, when Yosef saw that the brothers actually cared about Binyamin and refused to abandon him in Mitzrayim, he knew that the wounds had healed and that it was safe for him to reveal who he was and to begin the process of reconciliation.