Vartika, the NEET forms haven't been released yet and we are still unsure of the date. They might be tentatively released in the months of January or February. So let's say your exam is in February, there are 2 things here. If the NEET applications are released before your NIOS exam, your code will be 01 because you are still appearing for the qualifying exam to be eligible for NEET. But if the applications are released after your NIOS exam, your code will be 02 because then you have already written the exam. And you will select your State Board as your Board of qualifying examination because through NIOS you are not appearing for the entire 12th but are appearing for only 1 subject.