Final answer:
The piano is the element that can express richer harmonies and a wider range of notes due to its structure and capability to resonate a variety of overtones within its sounding board.
Step-by-step explanation:
The element that expresses richer harmonies, discords, and a wider range of notes out of the options provided is the piano. Wind instruments like the clarinet and flute can amplify tones through resonance in air columns, and the violin does use a sounding box to enhance its tones, but the piano, with its 88 keys and ability to play multiple notes simultaneously, can express a much broader dynamic range and complexity of harmonies. The piano's strings can resonate within its large sounding board, allowing for a greater variety of overtones and richer sounds that combine to form complex chords and harmonies.
Furthermore, the development of the piano over time, especially during the Industrial Revolution, allowed for improved mechanics, which made it even more versatile and powerful as a musical instrument. Therefore, the piano is well-equipped to deliver a wider range of notes and more intricate harmonies compared to the other options.