Playwrights are rarely involved in any part of theatre other than writing scripts

Which of the following is a true statement of this selection?

a) its composer uses the preexisting material without change from its original source b) its composer uses the preexisting material set out in voice pairs and in strict canon c) the composer shifts the borrowed music from its original duple meter to triple d) its composer subjects the preexisting material to a change from duple to triple time

In 12-tone composition, rows could be written __________

a) in spiral form b) in mirror form, or inverted c) to provide a strong sense of tonality d) based on Gregorian chant