Do you prefer to study alone or with other students in a group. Support your opinion with reasons and examples.

Well, the speaking is out of topic. The topic is "prefer to study alone A or with other students in a group B". You need to choose A or B. You choose A first, then at the end, you changed it to B.

You need to follow the topic whether it is an essay or a speaking topic. You should not put something new.

If this happens in real exam, the mark will be very low even though you talked it very well.