Sit Tight and Write On!
This is the answer because it SOUNDS right.
What if it turned out to be wrong? Disappointing, isn't it?
Having seen so many children falling into the trap of choosing what sounds right, we know that the only way to score is when you know the rules and the clues to look out for.
Well, grammar takes up only 10 marks in the MCQ.
That is not true! Grammar questions are explicitly tested in the grammar cloze, editing and comprehension cloze sections as well. Do you really wish to lose all these marks? We don't think so.
This answer is correct because...
How exactly can you get that mark? Will simply telling your teacher that this is the best answer be sufficient? Or will she/he be more convinced if you can actually explain why the answer should be such? I am sure you will agree that the correct explanation is going to be more effective.