A student has to mention the preference of medium at the time of making the application for examination.
The option to answer papers in HINDI should be exercised in total. Paper wise option is not available. The papers of a candidate who has not exercised his option to answer papers in Hindi, but answers them in Hindi, would not be valued.
In the absence of clear indication of preference at the time of making the application for examination, English will be taken as the preferred medium.