Answer:
C.
Step-by-step explanation:
Though the story is also about A, B, and D, the overall story is about C. The story begins with the enchanter turning the eldest and second eldest brothers into an Eagle and Whale, though the youngest escapes. He then goes to the castle to free the cursed princess, and to do so he needs to find a crystal ball. If I remember correctly, the ball will also save the brothers.
