Which term is associated with a harsh and discordant sound?

The term "strident" is associated with a harsh and discordant sound because it describes a quality of noise that is sharp, grating, and unpleasant to the ears. This word conveys a sense of intensity and discomfort that can evoke a strong emotional response, often making it suitable for descriptions of sounds that are jarring or aggressive.

In contrast, the other choices paint a very different auditory quality. "Mellow" typically refers to a sound that is soft, smooth, and soothing, often conveying warmth and ease. "Cordial" suggests a friendly and warm quality, but is not related to sounds at all. "Pleasant" refers to something enjoyable or agreeable, which is directly opposite to the harshness implied by strident. Therefore, the association of "strident" with a harsh sound makes it the fitting choice in this context.