Hi Ashish,

B.A. in Defence and Strategic Studies, is a 3 years undergraduate course. Some of the top colleges that offer this course include, 

Government Nagarjun Post Graduate Colleges of Science, Raipur

Guru Nanak College, Chennai

Deendhayal Upadhyaya Gorakhpur University, Gorakhpur

Dr. Ambedhkar Government Arts College, Tamil Nadu

Dhandai Mata Education Society's College of Arts, Jalgaon

All The Best