Final answer:
The A section of 'Caballito Negro' is defined by the particular ensemble used. Without reference to the score or reliable music literature, it's not possible to confirm whether it's option C or D.
Step-by-step explanation:
The A section of Caballito Negro (Little Black Horse) is characterized by the specific instruments used and the dynamics of the music. While options A and B describe the dynamic levels - how loud or soft the music is - they do not provide information about the instrumentation.
Therefore, we need to look at options C and D. Option C indicates that the piece is performed by soprano voice, piccolo, and percussion, while option D suggests a combination of soprano voice and orchestra.
To find an answer, we would need to refer to the score or a reliable source on the piece.
However, without that information, one cannot definitively select C or D. It is important when addressing questions related to music that the correct ensemble is identified based on the composer's intentions and the specific arrangements of the piece.