Why do many of Schoenberg's early twelve-tone compositions adopt traditional musical structures?

a. He was paying homage to the great Viennese composers of the eighteenth century.
b. He felt that while tonality needed to be abandoned, traditional forms should always be retained.
c.He felt he needed to incorporate familiar musical elements because his tonal system was so new.
d. He could not think of any revolutionary approaches to form.

c