Here is a way to fill in the blanks using your provided options:
Cora and Ruky are orphan siblings who take care of each other. Cora is the older sibling and has been like a mother to little Ruky. (E)
One day, Ruky frustrates Cora, and she makes a wish that instead of being crow-like, Ruky were really a crow. The wish appears to come true. (C)
Finally, Cora wakes up and discovers that Ruky is fine and human. (D)
So the complete story would be:
Cora and Ruky are orphan siblings who take care of each other. Cora is the older sibling and has been like a mother to little Ruky. (E: Cora has a gloomy personality, while Ruky is sunny and happy)
One day, Ruky frustrates Cora, and she makes a wish that instead of being crow-like, Ruky were really a crow. The wish appears to come true. (C: Ruky turns into a crow and flies away to live with other birds)
Finally, Cora wakes up and discovers that Ruky is fine and human. (D: Ruky and Cora stop being mad at each other and take comfort in things returning to normal)