Question 2. A thin transparent layer of oxide protects the metal titanium against corrosion. The same thin layer attracts artists interested in making their art with the help of technology. By using heat or electricity, an artist can thicken the oxide layer and thereby turn the metal a range of vivid colors.

According to the passage, some artists work with titanium because it

A. is transparent.
B. does not corrode.
C. generates its own heat.
D. can assume a variety of colors.