The correct answer is d) Return to a previous melody.
The music from the fourth verse of Boulanger's Psalm 24, which starts around 45 seconds into the piece, is described as a new section that contrasts with the music heard in the beginning. Based on this information, we can conclude that the correct answer is d) Return to a previous melody.
In this section, the music returns to a melody that was heard earlier in the piece. It is a continuation of a previous theme, rather than a new theme or a shift to a faster tempo. Additionally, there is no mention of the introduction of a new instrument in the question.
To summarize:
- The music from the fourth verse of Boulanger's Psalm 24, starting at 45 seconds, is a return to a previous melody.
- It is a continuation of a theme heard earlier in the piece.
- There is no indication of a shift to a faster tempo or the introduction of a new instrument.