Final answer:
The Snare Drum is the unpitched percussion instrument among the given options. Unpitched percussion instruments create rhythm without definite pitches, unlike pitched percussion instruments like the xylophone which can play melodies.
Step-by-step explanation:
Among the options provided, B. Snare Drum would be classified as an unpitched percussion instrument. In the field of ethnomusicology, instruments are often categorized based on how they produce sound. Unpitched percussion instruments do not produce definite pitches or tones when struck, making them ideal for rhythm rather than melody. The snare drum, along with others like the cymbals and castanets, fall into this category. While instruments like the xylophone (which uses tuned bars) and gongs (which may produce a pitch but are often considered unpitched due to their indefinite tone) are also percussion instruments, they are not the correct answer to this question.
Other unpitched percussion examples are the triangle and wood block, which are similarly used for rhythmic patterns rather than pitched musical lines. In contrast to unpitched instruments, pitched percussion instruments like the xylophone have bars or keys that are tuned to specific notes, enabling them to play melodies and harmonies.