Hi,

It depends on what you have for your best of four. If you had studied Economics as one of the subjects in your 12th boards then you can apply for BA honours in Economics without any deduction of marks but if you did not have economics in +2 or you did not include Economics in best of four then you will face a deduction of 2.5% from your best of four percentage.

Please check the official notice for more information:

https://www.du.ac.in/du/uploads/COVID-19/pdf/Illustrative%20examples%20to%20calcaulate%20percentage.pdf

Hope this helps.