The Cella, also known as the naos, is the inner chamber of a Greek temple, and it is the most sacred part of the structure. It typically houses a statue of the deity to whom the temple is dedicated, representing the physical embodiment of that god or goddess within the temple space. This statue was often elaborately crafted and positioned in a way that it could be venerated by worshippers.
The other options refer to different aspects of temple design or use. While a collection of artifacts and treasures may be found in other sacred spaces or museums, they are not the primary feature of the Cella. The main entrance of the temple is located at the front facade and serves as the passageway into the temple, but it is distinct from the Cella itself. As for the altar for sacrifices, this is typically located outside the temple, in a designated area where worshippers would perform rituals and offerings, away from the Cella where the deity's statue resides.