Dear candidate, The colleges in DU give the cut off criteria as per the best 4 subjects marks attained by the student in class 12th boards. So it's not compulsory for you to have studied sociology in 12th. For degrees in sanskrit, there is a compulsion to have studied sanskrit in class 10th. Therefore the best of 4 marks gained in 12th boards forms the basis of cut off.

Hope this was useful.