Third Generation Branch

There are three lines at the beginning of the novel? Parallel world development? If the ending is already determined, how will you choose? No cp, female protagonist, plain style, fairy tale, with BE line. The author wants to try to give a character different personalities and environments under the same world view, so that he can experience different experiences on three lines and come out with different endings. A cauldron, a knife, and a mirror, what path will the heroine take? (Newcomers looking for advice)