The image above shows Mount Rushmore, which is located in the U. S. state of South Dakota. Mount Rushmore is considered a relief sculpture because a.
it was carved into a rock surface on one side.
b.
it can only be viewed from a front perspective, rather than from all around.
c.
parts of the sculpture were carved so that over half of the image extends from the background to create shadowing.
d.
of all of the above reasons.