Bangalore

Screening is based on merit and you have taken two years extra plus your percentage is also not good, hence you might face some issue in the admission, for more details contact the college authorities:
https://www.shiksha.com/science/course/m-sc-in-computer-science-maharshi-dayanand-university-rohta

Please refer to the links provided below for details regarding a course in BBA hons from CMR University and Global Institute of Management Sciences. You should be able to compare the features of each college from the web page itself and then decide which college you would prefer to pursue BBA hons.
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To know about the hostel fee per year I would request you to get in touch with the college authorities as they will be able to give you accurate details.
For contact details refer: http://www.theoxford.edu/

You need to have some really solid reason to justify your bad grades. College admissions officers don't want to hear excuses unless the circumstances were absolutely out of your control.
Mostly all the colleges take into consideration your academics and extracurricular. Some may grant you admission

There is no provision to lower the MCA time duration for experienced candidates I.e. the MCA duration even for the experienced candidates will remain 3 years.

As per your marks, I will suggest to apply in Christ University and other government colleges in Bangalore. But, before getting admission, make sure about the placements of the college.

You must prepare for MHCET exam & try to get maximum % around 99.

I would suggest you to complete your class 12th first and then think about joining any institute.