Final answer:
A 3-d surface designed to be viewed from only one direction is called a c. relief, which is a type of sculpture that projects from its background.
Step-by-step explanation:
The question asks about a 3-d surface designed to be observed from only one direction. This type of sculptural work is known as a c. relief.
Unlike sculpture in the round, which is free-standing and can be viewed from all sides, a relief sculpture is attached to a background and projects from it. There are various types of relief, including high relief, low (bas) relief, and even sunken relief, where the design is carved into the material instead of projecting outward.