Final answer:
Aperiodic tones are considered to be noise, which contains a variety of frequencies without a harmonic relationship, unlike pure tones with a single frequency or complex tones with a regular pattern. Hence, option (A) is correct.
Step-by-step explanation:
Aperiodic tones are considered to be noise. Unlike pure tones which have a single frequency, noise contains a mix of multiple frequencies that do not have a harmonic relationship. Aperiodic tones lack the regular repetition pattern that characterizes pure or complex tones. Instruments like the trombone can produce a series of overtones, but the trombone, for instance, does not produce its fundamental frequency and only makes overtones. When discussing harmonics, it's important to note that harmonics are all multiples of the fundamental frequency.
For example, when the first overtone is the second harmonic, the second overtone is the third harmonic, and so on. Sounds produced by musical instruments, including overtones, contribute to their unique timbre. The combination of fundamental frequency and overtones differs from one instrument to another, giving each its distinctive character.