Nice to know that you want to be an IAS and wish you Best of luck.

Now regarding your question, I would say there is no such subject which can ensure your chances more. See UPSC is an examination which requires a special attention that is to get a job through UPSC you need to study specifically as per the UPSC syllabus. Thus there are no options available that can ensure you more about the selection. I would recommend you that you should take the subject you like the most. This is a very important point because if you take the subject you like then while studying it you will not feel bored or get exhausted. This will help you to study your BSc subject as well as your preparation for UPSC. So take the subject you like the most.

Now you can take some subjects which are in your UPSC syllabus like BSc Geography, Economics. But I assure you that the things you will learn in BSc will not be needed exactly in your UPSC preparation. Instead you will find that foundational knowledge to the subject is important. This is the reason why I stated that you should pursue the subject you like and keep a focused plan for your UPSC preparation.

To know more about UPSC visit the link below:

https://competition.careers360.com/exams/upsc-civil-services-exam

**Now as you have asked for the plan B and which have a research related field then I would say there are ample of such subjects. If you want to go for Physical sciences then you can go for BSc Statistics/Mathematics and then you can go for Applied Mathematics/ Data science. This not only have research options but also have industrial applicability and employability. Now you can go for Bio fields such as Genetics, Genomic Science, Virology, Microbiology, Biochemistry etc this fields also have a lot of research scope. Now apart from this you can go for Geophysics, Physics, Astrophysics, Nuclear Medicine, Medical Physics, Biophysics etc. All this fields you can go for if you choose to take Physics as your BSc course. Thus if you want to do research as plan B then you have a ample of subjects to do research in. The trending BSc's which you can go to have more research options (BSc) are:

• Statistics & Mathematics
• Physics
• Chemistry
• Biochemistry/Microbiology

I hope my answer helps. All the very best for your future endeavors!