题目内容：
材料全屏 Piano
【*】The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centuries--the spinet(小型立式钢琴), the dulcimer(洋琴), and the virginal(小键琴) In the seventeenth century the organ(管风琴), the clavichord(古钢琴), and the harpsichord(大键琴) became the chief instruments of the keyboard group, a supremacy they maintained until the supplanted them at the end of the eighteenth century. The clavichord's tone was metallic and powerful; nevertheless, because of the variety of tone possible to it, many composers found the clavichord a sympathetic instrument for intimate chamber music. The harpsichord with its bright, vigorous tone was the favorite instrument for supporting the bass of the small orchestra of the period and for concert use, but the character of the tone could not be varied save by mechanical or structural devices.
【*】The piano was perfected in the early eighteenth century by a harpsichord maker in Italy (though musicologists point out several previous instances of the instrument) This instrument was called a piano e forte ( soft and loud), to indicate its dynamic versatility; its strings were struck by a recoiling hammer with a felt-padded head. The wires were much heavier in the earlier instruments. A series of mechanical improvements continuing well into the nineteenth century, including the introduction of pedals to sustain tone or to soften it, the perfection of a metal frame, and steel wire of the finest quality, finally produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound, from a liquid, singing tone to a sharp, percussive brilliance.
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【单选】
What does the passage mainly discuss?（）
A
The historical development of the piano
B
The quality of tone produced by various keyboard instruments
C
The uses of keyboard instruments in various types of compositions
D
The popularity of the piano with composers
答案解析：