It totally depends on your skills and interest. But after B.tech, Management is the good option, Engineering joining management give multitasking ability for Engineers and also equally important in any organization If it is done from a reputed and recognised college. In nowadays, Many companies are hiring the students with dual degrees.

Some of the specialization options among which you can choose as per your interest-MBA in Business Analytics

MBA in Marketing

MBA in FinanceMBA in Logistics and Chain Management

Good Luck!