How can the amount of copper-containing waste produced during the etching process be reduced?

A. Increase the concentration of copper chloride etching solution
B. Decrease the concentration of copper chloride etching solution
C. Implement more efficient etching techniques
D. Use less circuit boards

C. Implement more efficient etching techniques

One way to reduce the amount of copper-containing waste produced during the etching process is to implement more efficient etching techniques. This can involve using advanced equipment and processes that allow for more precise etching, resulting in less excess material being removed and less waste being produced. Additionally, optimizing the etching process can help minimize the amount of chemicals and solutions needed, further reducing waste.