hey,

you are required to calculate aggregate of best four subject marks , however some subjects are mandated to be counted like english or any other language, sets of subject you need to include is different for all courses if you do not include those subjects then it will lead to deduction in your aggregate  like if you are willing to pursue B.A economics hons then you must have studied mathematics subject and have to include that in your best course.

to know more about same , what subjects you should include kindly go through the link mentioned below

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

good luck!

to know