I think ( D ) is the best answer because it clearely shows your feelings about the subject and make the listener eger to follow you
Answer:
The theme of a story is important because a story's theme is part of the reason why the author wrote the story. The author has a message he wants to share with readers, and he uses his story as a way to get that message across.
In the story, we know that Sergei uses his wishes for the goods of others,
The first one is to cure his sister's lung cancer, the second one is to cure his son's mental problems
Based on this, i think we can conclude that sergei has a kind hard and always want to help those around him without regards for himself
hope this helps