Which of the following is the largest brass instrument in an orchestra?

The tuba is recognized as the largest brass instrument in an orchestra. Its size contributes to its deep, rich tone, which provides a foundational support for the brass section and enhances the overall sound of the ensemble. Tubas are typically pitched in the bass clef and can have various configurations, including the BBb and CC tubas, which further emphasizes their large size and capacity to produce lower pitches compared to other brass instruments. This contrast is significant because while the trumpet, horn, and trombone each have distinct roles and ranges within the brass family, they are all smaller in size and produce higher pitches than the tuba. Therefore, the tuba's size and tonal characteristics make it the largest brass instrument commonly found in orchestras.