The main thing that this question is asking is which sentence does not have a formal tone. A formal tone for research writing usually means using more professional (instead of casual, everyday) language and free of your own opinions.
This means choice D is inappropriate because it is opinionated. Using "I think" is not formal tone.
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Answer: D) I think one of the most frustrating things about owning a cat is that they don't obey many commands.
It is interrogative because your asking a question. <span />
Answer:
The answer is A. She feels jealous of the lady
Explanation:
The reason behind is because the princess battles with her decisions since she doesn't want to marry the lady behind the door but instead she wants to marry the Prince herself. So our conclusion would be that she would choose the tiger out of jealousy.