BCA

B.Tech in CSE is engineering degree and better in comparison to BCA. MCA graduates are treated by IT industry equivalent to B.Tech CSE. BCA graduates get lower end apps development jobs, whereas CSE graduates are employed in both systems and apps development. CSE graduates get better salaries in comprising to BCA graduates.

Law is better, if you pursue it with full dedication.

For science students, your preference should as:
1. BCA.
2. BBA.
Both are the UG courses and offer good job opportunities in government and private sector. BCA will again insist you to pursue MCA to get decent jobs. But, as a BBA graduate you can directly prepare for government jobs as bank PO, SSC, etc.

First complete your graduation then appear for civil services exams conducted by UPSC and RRB.

BBA-CAM can not be equated equal to BCA which is purely a technical job oriented degree. If you want to have technical career, you may opt for MCA but if you want to have techno-managerial career you may opt for MBA-IT.

BCA is a 3-year program and not will make you an engineer. B.Tech is a 4 years program which can get you an engineering degree. BCA provides a sound base on which advanced computer applications can be developed.