fill the blank with 1 single word: Elle joue --- piano

Elle joue DU piano.The issue here is: using prepositions You normally JOUER + Àand should know that this is because Jouer is a verb that takes the preposition à before a noun or infinitiveso to answer this question you must know the idiomatic use of JOUER + DE for musical instruments you must also conjugate DE appropriately:de + le (piano being masculine) = DU