Hello Sakshi

The best of four subjects should include

• One language (core/elective/functional)
• One subject in which admission is sought
• Any 2 academic /elective subjects

You can include the computer science marks in the best of four.The subjects other than the academic /elective subjects listed will undergo a deduction of 2.5marks.So go through the given article for further clarification

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

Subject like english is must and maths marks in science subjects if you are asking for web application I think you are telling for informatics practices subjects so you can give informatics practices in the one of the four subjects.

In case of DU including english that subject should be present in four subjects with which related to you are going to do B.Sc in DU.