Hello,

First of all the eligibility criteria of UPSC is passed graduation in any discipline from a recognized university, there is no specific aggregate require in this case, candidates in the final year of graduation too are eligible to apply provisionally, they need to attain 21 years as on 1st August of the appearing year, now coming to your question as I told there is no such restrictions of belonging to specific stream when it comes to appearing for UPSC, if you have a look at previous year toppers they come from as diverse backgrounds as medical, engineering, commerce, science etc, so it's all about your preparation and strategies you follow that help you sail through this tedious exam, now between BBA and BSc Maths, there is optional paper of Maths in UPSC, so in this regard you may have advantage that is in future you may choose it as your optional subject, as there is no subject of management as optional paper, however choosing a career is a vital decision, so you have to look at various factors for example what are your career options apart from UPSC, BBA is a professional degree hence from that sense it's more valuable to that of BSc Maths, so you have to analyze lot of stuffs such as what if not upsc, what are the back up plans you're looking at, your interest in a specific field is highly important when it comes to choosing your graduation as you will spend your precious three years, so take decision accordingly, and you can appear for UPSC with graduation in any stream from a recognized university as I already mentioned.