Among the 3 B-schools you have mentioned, FORE School of Management (FSM) and IMI Delhi are private B-schools whereas Delhi School of Economics is a public institute. The basic information of these 3 B-schools are as follows:

You can also check the Careers360 B-School Ranking for 2018 to decide which B-school you should go for:

https://bschool.careers360.com/colleges/ranking/2018

Final decision should be yours based on factors like placement figures, industry academia sync, faculty strength, infrastructure and resources among others.