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.
------
Answer: D) I think one of the most frustrating things about owning a cat is that they don't obey many commands.
Answer:
True
Explanation:
Things you do in your childhood form the basis of your adulthood.
Answer: 2: my brother can't sing well.
3: My dog can catch the ball.
4: My grandmother can't use a computer
5: My sister can ride a horse.
6: My grandpa can't speak English.
Explanation: Hope this helps :P
