Select the revision that makes the following fragment into a complete sentence. First used in Japan in the 1600s to illustrate books.
A. They were first used in Japan in the 1600s to illustrate books.
B. First used in Japan by master artists in the 1600s to illustrate books.
C. First used in Japan in the 1600s to illustrate books and still employed today.
D. Although they were first used in Japan in the 1600s to illustrate books.