The three courses you mentioned i.e M.tech, Ms and Mba, you must have to choose between the M.tech and MBA. Both M.tech and MBA have good job opportunities and also have good growth. After Completing B.tech, M.tech will not be much difficult as you are going in a same line. But if you go for MBA though it may be different from what you have studied till date, but it has a great scope in future. So before choosing any course, you must think about in which course you have more interest.
All the best.