Hidden-surface removal is the process of:

a) discarding those objects that fall outside the view volume
b) applying a parallel projection rather than a perspective projection
c) identifying parts of surfaces that are in a shadow
d) identifying surfaces that are blocked from the camera’s view

Option A.

Explanation:

In 3D computer graphics, this process determines which elements should not be visible from the desired point of view, and will prevent them from rendering. Thus, objects that lie behind opaque surfaces such as walls or panels, will not be rendered.

A good rendering algorithm helps to optimize the graphic engine because it will load as few elements as possible. Therefore, in larger worlds, the engine will remain at a stable speed and will be more efficient.