April 2026 CBLE, question 38

Of the four choices below, which is the best CLASSIFICATION of sound insulating panels? The panels are two centimeters thick and imported in one by one half meter sections. They are composed of wood shavings agglomerated with a cement binder and are sanded but otherwise unfinished. To a casual observer, the panels look like a collection of randomly oriented wood slivers pressed together into a flat, rigid board. The intended use is for acoustic sound absorption for the construction of areas such as music studios.