Hi, While you are filling your form for reservation seats. Please make sure that you check what category you really belong to. Maybe your sub caste belongs to SC category or vice-versa. Even after thorough checking you still do not have a option choose others if there is any. If not that you can leave the whole question if it is not compulsory to answer. Leave it in ST category and that's it, move forward. Hope this helps. All the best!