Depends on your passion and your interest. If you are OK with both go for better college. Check placements records and learning opportunities in that college.

If I would suggest one of them then I must suggest you to choose instrumentation engineering.

Scope of this branch is good , you feel like you are doing engineering and not medical, placements from this branch is also very decent .

Biomedical and instrumentation are both core branches so you have to make sure that whatever college you're choosing has the necessary infrastructure.
Apart from that, please specify which instrumentation field is this? Does it run parallel with electronics or is it biological instruments?

Dear Dipak
My suggestion depends upon your passion. Just go through this once. Once go through the subjects in both the branches and if any subject is coincide with your passion and by taking suggestions from seniors you can opt that branch. And if you really want my choice then instrumentation engineering will be good as per now and after few years also it is having demand.
All the best.