The word used to refer to the material with which the artist works is __________

A notable aspect of this piece is its?

a) quotation of Beethoven's Third Symphony b) quotation of Wagner's "Tristan chord" c) a minor-mode quotation of Frère Jasques d) quotation from Smetana's The Moldau

What is overdubbing?

a) Covering a song by another artist b) Fixing mistakes in the studio c) Multiple recorded tracks that are assembled in the studio d) Recording over used tape from another session