Why the poor grades at your current school? Also, I have a feeling that your high SAT scores are a reflection of the dumbing down of American schools, which means that you’ve more than learned the material expected to have been mastered for the SAT. Most US students who are B/C students don’t score anywhere near that on the SAT.
Low grades and high SAT scores are indicative of smart but “uninspired” (read lazy) students. Every field requires some amount of plain old hard slogging work, some more than others. If your SATs and AP exam scores are both fantastic, plus you do extremely well academically henceforth, I think you still have a shot, especially if you can develop a “hook” - some area in which you have stellar achievement, like starting a successful business. So the game is far from over for you, but you really need to pull those grades way up.
And yes, there are many other excellent options for you besides Wharton, Harvard, and U Chicago. So don’t be discouraged. Focus now on grades and coming up with a business idea that you can develop from India (assuming that’s where you are). All the better if it’s something that helps the poor to improve their own economic situation, in the way that early dissemination of cell phones in rural areas, microloans, bicycle irrigation pumps for farmers, solar panels for light to study by after dark did. If you can come up with something original that helps people to improve their economic situation, that can show some degree of early success, I suspect that would be very interesting to a business school admissions committee, much more so than joining your school’s stock market club.
Look at this organization, Kickstart (not kickstarter). http://kickstart.org/
Does India have something like this? Is there some other product that might help Indian farmers adjust to climate change? Something on a small, model scale? Is there some way that you could help Kickstart expand to India?
Look up other successful programs for micro startups for the rural or megacity poor, that have helped people. It would give you ideas for a business-related project you could do in India. It doesn’t have to be a brand new, first time ever idea. It can be something that has been tried (and worked) in other areas of the world, that might be successful in your country, or some variation on the theme. The first person to have flown a plane in Australia still made the record books, even though it wasn’t the first flight ever. Starting up something unique in your country that shows drive, creativity, leadership, and social justice through self-earned economic advancement is just the thing to set you apart when applying to business school.