A minor requires an extra nine hours of curriculum in the same area. You can achieve this with elective courses in the same area (i.e., same prefix: MKT, MGT, BIS, ACC, FIN, etc.). Your core classes cannot count toward the minor. For instance, MKT 8153 is a core marketing class required for the MBA. Therefore, you would need 9 extra hours of marketing beyond that class. Of course, your elective course(s) do count toward the minor.
So, you can achieve a minor by taking 36 hours (3 hours of elective +two additional courses in the same prefix area) for students entering the program prior to Summer 2019. Students starting summer 2019 or after can achieve a minor with 33 hours (6 hours of electives + one additional course in same prefix area).
You advisors can assist you if you want to consider earning a minor, which will appear on your transcript. Both 6000 level and 8000 level graduate courses in the same area count toward your minor.