【单选题】

1David Smith worked primarily in iron, exploring its possibilities more fully than any other sculptor before or since. To Smith, iron spoke of the power, mobility, and vigor of the industrial age. Smith was born in Indiana in 1906, the descendant of a nineteenth- century blacksmith. His iron sculptures flowed naturally out of the mechanized heart ofAmerica, a landscape of railroads and factories.As a child, Smith played on trains and around factories, as well as in nature on hills and near creeks. He originally wanted to be a painter, but after seeing photographs of the metal sculpture of Picasso in an art magazine, he began to realize that iron could be handled as directly as paint.

2 Many of Smith’s sculptures are "totems" that suggest variations on the human figure. They are not large iron dolls, although several have "heads" or "legs." Still, they forcefully convey posture and gesture. Their message flows from the internal relations of the forms and from the impression of tension, spring, and alertness set up by their position in space.
3 Later in his career, Smith produced two series of sculptures in stainless steel: the Sentinels in the 1950s and theCubis in the 1960s. He also began placing his sculptures outdoors, in natural light, where the highly reflective stainless steel could bring sunlight and color into the work. In the late afternoon sun, the steel planes of theCubis reflect a golden color; at other times, they have a blue cast. The mirror-like steel creates an illusion of depth, which responds better to sunshine than it would to the static lighting of a museum.
What can be inferred about the Sentinels and theCubis
A、They are the best-known examples of Smith’s "totem" sculptures.
B．Smith originally intended to use iron instead of stainless steel.
C．The Sentinels are made of blue steel, and theCubis are of gold steel.
D．They each consist of a number of pieces placed in outdoor settings.