Final answer:
A mausoleum is the correct term for an entrance to a burial tomb, distinguishing it from other architectural elements such as facade, portico, and parapet.
Step-by-step explanation:
The best term for the architectural element depicted as the entrance to a burial tomb is a mausoleum. This term specifically refers to a grand tomb or building constructed as a burial chamber. In the context provided, none of the other options accurately describe an entrance to a burial tomb. A facade is the face of a building, typically referring to the front. A portico is a series of columns or arches in front of a building forming a covered walkway or porch, which is not exclusively for burial purposes. Lastly, a parapet is a low protective wall along the edge of a roof, bridge, or balcony, which is not related to burial architecture.