Which percussion instrument is commonly associated with Spanish music?

The castanets are the correct choice as they are a traditional percussion instrument frequently associated with Spanish music and dance, particularly in flamenco. This instrument consists of two shells joined on one end and produces a clapping sound when struck together. Castanets play a crucial role in the rhythmic and expressive elements of Spanish performances, often complementing dancers and other musicians by providing a distinctive, sharp accent.

In contrast, while the tambourine has a presence in various musical traditions, including some Spanish music, it is not as emblematic of Spanish culture as castanets. The bodhran, a frame drum originating from Ireland, is tied to Irish music and lacks a connection to Spanish styles. The marimba, a wooden percussion instrument from Africa and Latin America, is also not traditionally linked to Spanish music. Therefore, castanets stand out as the quintessential percussion instrument representing Spanish musical heritage.