The piano was not an important instrument during the Baroque era, which primarily featured the organ and harpsichord. The piano was developed later, in the Classical period. Understanding these distinctions helps clarify the evolution of keyboard instruments in music history. ;
The Baroque era did not prominently feature the piano, as it was developed later. The key instruments of this time were the organ and the harpsichord, essential for various musical compositions. Therefore, the correct answer is A. piano.
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