See if you have given the BSc Mathematics Hons exam and passed the first year then you my have to use the code 5. But as you didn't appear for any examination which means that you are just like a normal dropper then you have to use code 2.

The code 2 is for those students:

• Completed 12 years of school education from CBSE/ICSE or any other boards with the last 2 years having the subjects English, Physics, Chemistry, Biology/Biotechnology, or Mathematics or any other elective as a major subject .
• Students who have passed from NIOS/other open schooling board with Biology/Biotechnology as one of the subject in 10+2.
• For the droppers.

To know more in details about all this codes visit the link provided below:

https://medicine.careers360.com/articles/neet-qualification-codes

I hope this answer helps. All the very best for your future endeavors!