Which of the following is a material that was traditionally used in hand-drawn animation?

Celluloid is the correct answer because it has a long-standing history as a fundamental material in the production of hand-drawn animation. Originally created in the 1860s, celluloid became the preferred choice for animators since it could be easily printed, painted on, and layered to create transparent images. This allowed animators to create a sense of movement by placing multiple frames atop each other, effectively facilitating the animation process.

While acetate and plastic are more modern materials that succeeded celluloid due to their durability and ease of use, they were not the traditional media for hand-drawn animation. Cardboard, on the other hand, is typically not used in hand-drawn techniques as it lacks the flexibility and transparency that celluloid provides, making celluloid the quintessential choice for early animation projects. The evolution of materials in animation illustrates the transition from celluloid to more contemporary options, but celluloid remains the hallmark of traditional animation practices.