Answer:
It would basically be based on how you study and what your room is like. But my opinion would be
Bedrooms are Too Comfortable- which causes you to want to sleep or not due your work
Bedrooms are dimly lit- Which makes it hard for you to see your work and see anything
Bedrooms are too small- You will fell crushed and hard to focus (I would most likely choose this answer)
Bedrooms are messy and cluttered- You will not be able to concentrate and make it hard to study or do school work. ( I would choose this because I have experienced with this and I score higher in a cleaner environment and able to focus more)
Explanation: This would all depend on how you best work.
Hope this Helps!!