Final answer:
A stela is the correct term for an upright stone slab with carved or inscribed surfaces, often used as a monument or marker, distinct from an obelisk, cenotaph, or plinth.
Step-by-step explanation:
Among the options given, the correct term for an upright stone slab or pillar with a carved or inscribed surface used as a monument or marker is a stela. A stela (or stele) is often carved in relief and may have inscriptions in various scripts like cuneiform, which was used in ancient civilizations such as the Babylonians. This differs from an obelisk, which is a tall, four-sided, tapered monument ending in a pyramidal top and was commonly used in ancient Egypt. Options like a cenotaph refer to a monument erected to honor people whose remains are elsewhere, and a plinth is a base or platform upon which a column, pedestal, statue, monument, or structure is placed.