Which trumpet sounds as written?

The C trumpet is the correct choice because it is a straight-instrument that sounds concert pitch as written. When a musician plays a C on a C trumpet, it produces the note C in the actual sound, meaning that the notation reflects exactly what is heard. This characteristic makes it a common choice in orchestral settings and for advanced trumpet players, as it simplifies reading music in concert pitch.

In contrast, other types of trumpets like the Bb trumpet are transposing instruments. When a note is written in concert pitch, the Bb trumpet will play a whole step lower than written, which means if a Bb trumpet player reads a written C, it will sound like a Bb. Similarly, the D and Eb trumpets also transpose, producing notes that differ from written pitch. Hence, they do not sound as written in the context of concert pitch.