Hello Hritik. You must see the official answer key released by NTA. If you have done so then the answers have been marked by NTA authorities. If you have attempted all 3 questions in B.Arch Drawing correctly then you can challenge the answer key during 15-17 January by visiting the official portal of JEE Main 2019.

You can refer the following links-

https://engineering.careers360.com/articles/nta-jee-main

https://jeemain.nic.in/webinfo/Public/Home.aspx

Hope this helps. For any other queries feel free to comment down below.

All the best!