Hi,

Most probably the reason might be that you have scored low in your class 12 Board examination. So, as you have passed your class 12 already, you cannot repeat the class as only failure candidates are allowed to do so. So, you can appear again under the improvement category if you want to improve your marks in class 12 examination. You can choose the subjects in which you have scored low or could appear again for all the subjects as per your wish.