Ari is reading the score for a piece of vocal music with one staff with the letter S to the left of the clef. What does this MOST likely mean?

1. It’s a choral octavo for sopranos only.

2. It’s a mass with soprano as the highest voice.

3. It’s an oratorio with soprano suggested for the lead.

4. It’s a solo piece for soprano.

4. It’s a solo piece for soprano.