Which instruments are included in the brass section?

The brass section of an orchestra is characterized by instruments that produce sound through the vibration of the player's lips against a metal mouthpiece. The correct choice includes the trumpet, trombone, french horn, euphonium, and tuba, all of which are designed to create powerful, resonant tones characteristic of brass instruments.

These instruments are typically constructed of brass, and they use valves or slides to change pitch. Their rich, bold sound and ability to play both melody and harmony make them essential in orchestral and band settings. The presence of a range of brass instruments, from the bright and piercing trumpet to the deep and sonorous tuba, allows for a wide variety of sonic textures and timbres within musical compositions.

The other choices include woodwind and string instruments, which do not belong to the brass family and therefore do not fulfill the criteria set by the question regarding the instrumentation of the brass section.