BBA

You need atleast 60% marks in 12th to get into Christ.

Nothing but the HR. This is the best in class specialisation for girls. If you take a survey, more than 70% of the MBA girls candidates will choose HR as an option. This is because you can sync both your family life and corporate life together.

IIM, Indore would be best for integrated courses.

BBA+MBA is a good option,
Admission procedure for the 5-year Integrated Programme in Management (IPM) at IIM, Indore is you need to clear IPM Aptitude Test (AT). A computer based test for the course conducted in May. The candidates are selected on the basis of overall performance in AT and personal

I'm not sure if MBA colleges offer PhD. I guess you are looking for PGD (Post Graduate Diploma) in Business Management. The average salary for the top B-Schools is in the range of 12 lakh to 19 lakh. For colleges which fall in the second grade, the average salary ranges from 8 lakh to 12 lakh. For o

B.Tech students have advantage of strong quantitative aptitude, so they are good with numbers. Despite of choosing other courses, if your quant is strong, one can score better and hold good positions.

Digital marketing and data analytics are good to choose from as they have good scope.

MBA in IT will not lead your son to software development, but it will lead him to software marketing and other infrastructural maintenance.
All the best.

Hi Sunny,
You can go through this link for REVA information:
https://www.shiksha.com/bba/course/bbm-industry-integrated-reva-university/201576
All the best.