Hello, As per your query i would like to tell you, you will enter code 2.
If you entered code 3 there will be no problem.Correction window for neet form will open from March 12 to March 16.you will correct your mistake at that time.

Hope it helps
Regards
Dr Parmanand Agarwal
MBBS MD
Career counsellor

The correction window will be open from March 12 (tentatively 10.00 AM) to March 16, 2018 (tentatively 11.59 PM). As per the available information from NEET 2017, CBSE only allows candidates to make changes to their State Code of Eligibility, Category, Disability Status and uploaded documents. This year onwards, CBSE has said it will not allow candidates to change their exam centre or language of exam in the correction window. 
The below information is based on NEET 2017 guidelines.

Q. I entered the wrong qualification code in my NEET application form? Will I be able to correct it?

A. No, the correction window did not have such a facility last year. However, candidates should nevertheless check their form on March 12 and see if they are permitted to make any changes to the fields in which they made mistakes.

Hi Yogita,
CBSE has just now released a new FAQs, in which they have mentioned that you can correct your qualifying code during the correction window ie., March 12 to March 16, 2018.
Please read the CBSE FAQs.