Hi Shubham! I would suggest you revise your board exam syllabus thoroughly to have a strong hold on the test's syllabus. Apart from your textbooks, do read the newspaper and current affairs magazine regularly. These would not only enhance your knowledge on GK but would improve your vocabulary as well. Other than that, for the reasoning sections, try solving various puzzles and analytical caselets. Apart from these, some of the books are as follows:

• Perfect Study Resource for - Delhi University (DU) BMS Entrance Test  (English, Paperback, Arihant Experts)
• How to Prepare for Quantitative Aptitude by Arun Sharma
• A Complete Self Study Guide BBA/BBS/BBM (Bachelor of Business Administration/Studies/Management) Entrance Examinations 2016 5 Edition  (English, Paperback, Arihant Experts)
• Basic English Grammar book by Wren & Martin