SHE STUDIES VERY HARD. THIS HELPS HER GET GOOD MARKS.A. SHE STUDIES...

13.She studies very hard. This helps her get good marks.A. She studies very hard, which helps her get good marks.B. She studies very hard, this helps her get good marks.C. She studies very hard which helps her get good marks.D. She studies very hard, which this helps her get good marks.