Concept:
Animal byproducts are materials that are not the primary muscle meat but have significant industrial value.
• Horns and hooves: Composed mainly of a tough protein called keratin.
• Keratin: A fibrous structural protein that is durable and can be molded when heated.
Step 1: Properties of Horn as a raw material.
Horns are hard, durable, and possess a unique aesthetic grain.
When treated with heat and pressure, they can be flattened or shaped.
Step 2: Industrial applications.
Because of their durability, they have been used for centuries to make small tools.
They are ideal for buttons, decorative combs, and handles for knives (cutlery).
Step 3: Identifying the comprehensive option.
Horns are even used in high-end furniture inlays and ornaments.
Therefore, Option (A) covers the widest range of correct historical and modern uses.
Final Answer: (A)