Hi, there some important instructions that you should know while calculating best of four percentage for Delhi University:

•  You need to include one compulsory language that is English
•  Your second subject should the one in which you wish to seek admission, in youe case that is   Political science. If you don't include that subject then 2.5% marks will be deducted from your   best of four percentage
•  The next two subjects should be academic/elective subjects according to List A. If you don't include subjects as per List A then 2.5% marks will be deducted from your best of four percentage.

In order to see the subjects included in the List A and for further information regarding best of four  check the link below 

https://university.careers360.com/articles/delhi-university-admissions-how-calculate-best-of-four-marks

Good Luck