Agribusiness is a Post Graduation course and we have few top B-schools that offer this course. You can check the list at: https://bschool.careers360.com/colleges/list-of-agriculture-business-management-colleges-in-india . But after your 12th, you should do a Bachelor's course and we do not have Undergraduate courses in Agribusiness in India yet. But there is Indian Council of Agricultural Research which conducts Undergraduate and Post graduate courses. The entrance exam is ICAR AIEEA. They have extended their last date for applications until April 30th. You can benefit from this. You can complete your Bachelor's from here and then appear for CAT or any Management entrance exams and take up ABM. Please read our article for more information: https://university.careers360.com/articles/icar-aieea