Business Law

First of all, both are very different areas and they shouldn't be compared, but I would still answer it as to the best of my knowledge.
There is no official data available in India about the number of lawyers in both areas and about their salaries so it becomes tough to compare both.
Business law is about disputes between firms, companies, partnerships, and small businesses.
All these people or most of these companies, partnerships, and firms have their fixed lawyers and when any dispute arises their lawyers fight (I mean the same lawyer for that company), but when it comes to consumer protection laws, it is emerging day by day because awareness among the consumers is increasing and the number of cases is also increasing day by day and they don't have any fixed lawyers.
So, from this point of view, consumer protection law has more scope.

Hi,
Yes, you can join law colleges after doing 12th from commerce as LLB 5 year program can be done after the completion of +2 from any stream. There are various law schools, in order to get admission in most of the Law Institute one has to appear for entrance examination. The most common entrance exam for admission in LLB program is the CLAT (Common Law Admission Test). This is an all India entrance examination conducted by 14 National Law Schools and Universities for admissions to their under graduate program. To be eligible for the test candidate must have passed the +2 level of exam from recognized board with a minimum of 50% marks [45% for reserved candidates] and must not have crossed the age of 20 years [22 for reserved candidates].
List of some colleges offering admissions on the basis of CLAT scores:
NALSAR University of Law, Hyderabad
National Law School of India University [NLSIU], Bangalore
WB National University of Juridical Sciences [NUJS], Kolkata
Dr. Ram Manohar Lohiya National Law University [RMLNLU], Lucknow