Roman temple architecture was influenced by both Etruscan and Greek traditions but developed its own distinct characteristics.
One prominent feature of many Roman temples is that they were built on a high raised platform or base, which was typically accessed by a flight of stairs at the front. This platform is called a podium.
Let's analyze the options:
(a) Podium: In Roman architecture, a podium is a raised platform or base upon which a temple (or other significant building) stands. It elevates the structure and often has a prominent frontal stairway leading up to the temple entrance. This matches the description.
(b) Pediment: A pediment is the triangular gable end found above the horizontal entablature, typically at the front and rear of classical temples (Greek and Roman). It often contains sculpture. It's a roof-related element, not the platform.
(c) Cella (Naos in Greek): The cella is the inner chamber or sanctuary of a classical temple, which housed the cult statue of the deity to whom the temple was dedicated.
(d) Pronaos: The pronaos is the vestibule or porch at the front of a classical temple, typically enclosed by the side walls of the cella and a portico of columns, leading to the cella entrance.
The architectural element described as a "raised platform accessed by a stairway," often found in Roman temples, is the Podium. This feature distinguished many Roman temples from Greek temples, which often stood on a stepped base (crepidoma) accessible from all sides, rather than a high podium with a frontal approach.
\[ \boxed{\text{Podium}} \]