Some students attending a small university with a well-known choir live off campus. From the fact that all music majors are members of the choir, a professor in the music department concluded that none of the students who live off campus is a music major. The professor's conclusion is properly drawn if which one of the following is assumed? ['None of the students who live off campus is a member of the choir.', 'All students who are members of the choir are music majors.', 'Some of the students who do not live off campus are not music majors.', 'All students who live on campus are music majors.']