MBA Placement

Ankit, BBA launches you headfirst into a professional career after class 12; it's much more skill specific than a B. Com. If you are very sure that your aptitude matches to the management study only, your only goal is to get into management career, then BBA would be the best choice for you.
If you're good at crunching numbers or want anything to do in the fields of formal finance like CA, then a B.Com degree should be your clear first choice. Though you can pursue an MBA after B.Com, a managerial MBA is better backed up by a BBA background, especially if further supplemented by solid post-undergraduate work experience.
A step further, there are many good universities offering dual/ integrated degrees like BBA-MBA, B.Com-M.Com, B.Com-MBA etc too.

Ashwin, there are many private universities around that provide placements to UG students too. But then the pay package is generally not that good that you can expect after a PG course. So, you can go for MBA.
These days, we have many specializations available like marketing, finance, HR, operations, IT, international business, hotel management, tourism and hospitality management, hospital management, event management, e-commerce and so on. Choose a specialization as per your interest.
Now for admission, some institutes like IIMs, XLRI, prefer CAT/XAT/ MAT scores only for admission to MBA course. And to appear for CAT/XAT/MAT etc student needs to have 50% in graduation. But eligibility criteria varies for various Management Institutes or Universities, they can take different %age in graduation along with CAT/ MAT/ XAT scores.
Another way of admission is internal tests or admission criteria of individual Management Institutes or Universities like LPU, Amity, GD Goenka, etc.
Go ahead, take admission in PG course.