Plan D - Hashem's
Even though the brothers had three different plans for 'getting rid' of Yosef, God's plan was quite different. At this point in the story they are totally baffled, as they have no idea what happened to Yosef. Nevertheless, they still don't want their father to worry about his fate (or don't want him to accuse them), so they plot one final plan which is ironically quite similar to their original plan (see "chaya ra'ah acha'lat'hu" [37:20] and compare to 37:33). They dip Yosef's coat in blood and send it to their father (see 37:31-32):
"And he [Yaakov] recognized it and said, 'My son's "ktonet," "chaya ra'ah acha'lat'hu; ta'rof, ta'raf Yosef" - he was surely devoured by a wild beast.' " (37:33)Ironically, Yaakov reaches the same conclusion that the brothers themselves may have reached, but for a very different reason!