Most of Western music since the Renaissance has been based on a seven-note scale known as the diatonic scale, but when did the scale originate? A fragment of a bone flute excavated at a Neanderthal campsite has four holes, which are spaced in exactly the right way for playing the third through sixth notes of a diatonic scale. The entire flute must surely have had more holes, and the flute was made from a bone that was long enough for these additional holes to have allowed a complete diatonic scale to be played. Therefore, the Neanderthals who made the flute probably used a diatonic musical scale.
In the argument given, the two portions in boldface play which of the following roles?
A. The first introduces evidence to support the main conclusion of the argument; the second is the main conclusion stated in the argument. B. The first introduces evidence to support the main conclusion of the argument; the second presents a position to which the argument is opposed. C. The first describes a discovery as undermining the position against which the argument as a whole is directed; the second states the main conclusion of the argument. D. The first introduces the phenomenon that the argument as a whole seeks to explain; the second presents a position to which the argument is opposed. E. The first introduces the phenomenon that the argument as a whole seeks to explain; the second gives a reason to rule out one possible explanation. 答案是A