Hello,
A b.tech student if decides to go for M.A. he/she can take any specialisation of their interest and need. However in some universities and colleges they require specific course in undergraduation as eligibility. However such cases are rare therefore you are free to explore plethora of options like psychology, geography, philosophy, urban development, public policy etc.
Hope it helps
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile