What should I take among IIT Delhi textile, IIT Kharagpur biotechnology, and IIT Guwahati engineering physics?

The choice of college and branch totally depends on your inclination and career prospects. Yet, a few pointers you might consider 

For MBA/ non-core jobs/Startups: IIT Delhi Textile is the best choice if you are looking for any 3 of these options. Its excellent location provides enough exposure to give you access to unimaginable opportunities. Many events hosted by industry experts, CEOs of big companies, and successful entrepreneurs will give a better insight into the startup culture. Moreover, students preparing for competing exams can easily access coaching centers nearby.

Research in Biotechnology: If you are interested in research in general or Biotechnology specifically, then the Biotechnology at KGP is an excellent choice. It is one of the most demanding fields in terms of research and general growth. With a good CGPA, you can find a research internship or you can apply for MS or Ph.D. Even job opportunities are plentiful. 

Campus: IIT Delhi is better because of its small size and location

Lastly, Engineering Physics from IIT Guwahati should be considered only if you are genuinely passionate about Physics and want to pursue a research career in the same. The curriculum comprises high-tech mathematical concepts and is a good option to pursue a career in economics and computer science.