A cartridge is detachably mountable to an electrophotographic-image-forming-apparatus main assembly including light emitting and receiving portions. The cartridge includes an electrophotographic photosensitive drum, a developing member, a driving force receiving portion, first and second rotatably connected frames, the first supporting the drum and having a memory, and the second supporting the developing member and having a developer accommodating portion, a main-assembly-contactable electrical contact, first and second light guides whose respective entrance and exit are opposable to the emitting and receiving portions, respectively, first and second cartridge positioning portions engageable with first and second main assembly positioning portions, and a cartridge limiting portion abutting a main assembly regulating portion to limit rotation of the cartridge which otherwise occur about the cartridge positioning portions when the driving force receiving portion receives a driving force from the main assembly.