Science

Well, the answer to this depends on where do you see yourself in the future. What do you actually dream of doing? What do you think you will really enjoy doing
B.Com (h) opens up accounting avenues. You can pursue CA along with it but then you will have to do a correspondence course as the new rule of DU does not allow regular B.Com (h) students to pursue CA too. You must have heard about the Big4: KPMG, Deloitte, E&Y, PwC. If you dream of working in these audit companies then this is the apt choice. My personal advice would be to opt for a regular course if you are getting good colleges like SRCC, LSR or so. Believe me, the experience you get there is unmatched and you will cherish it forever. Economics (Hons) does not have accounts in its syllabus. You will get to read subjects like Macro eco, Micro eco, International eco, Stats, Maths, History of Indian eco, environmental eco, etc. If you want to do research-based work or policy-making and/or wish to become a college professor then this is the right choice. Masters in economics is the most preferred choice after this course which is also mandatory for becoming a professor or getting into Indian Economic Services (IES)
There are three other courses that you have not mentioned but I think they might interest you. BBE, BBS, and BFIA. DU conducts an entrance exam for admission to these courses. The final merit list is drawn on the basis of Boards exam marks, entrance test score (BBE) + GD-PI score (BBS, BFIA)
BBE can be thought of like an amalgamation of B.Com (h) Eco (h) and BBA. It is light on accounts (just one semester) but has a good amount of economics and management subjects. There is law too but just for one semester. So it is an all-round course which develops a good base for higher studies. Though I will caution you that some students end up feeling that they are a jack of all trades but master of None. Some notable colleges offering this course are SGTB, Gargi, and Shivaji. One can go for MBE/MBA/ M.A. Eco etc. After this course.

If you're interested in some sort of career, plan it accordingly! For example, you wanna be a chemist, go for a B.Sc. In Chemistry. And similarly, to be a physicist or if some research drags your interest in physics, then, be on Physics! That's it!
And if you are opting to settle for better, then, B.Sc. Chemistry is for you! Physics degree must be accompanied by a Masters degree, but a chemistry Bachelors degree could do it better in fetching you a job! I, personally, had my uncle go for a job in a pharmaceutical company after he completed his B.Sc. PCM (Physics Chemistry Maths). (And he was admitted as his course included chemistry!). .