Before you sell your MBP to anyone you have to repartition the drive and reinstall the original version of OS X that came on it when it was new. Depending on what version of OS X came on it when it was new the steps to do that are slightly different.
So what model year is your Mac and what version of OS X came on it when it was new?
You can not sell it with one of the download only version of OS X installed on it unless that version came on the system when it was new. Those versions of OS X that you bought, Lion and Mt Lion, or downloaded for free, Mavericks, from the Mac App Store are tied to Your Apple ID and can not be transferred to another individual.
You can't or practically transfer any software downloaded from the Mac App Store to the new owner of the machine, even if it was free. That includes , so if you upgraded to OS X 10.7 or later, you must the original OS, either from the installation media, if applicable, or by booting into Internet Recovery ( at the startup chime.) If you installed from discs or a read-only USB key, deliver those to the new owner.