Lean manufacturing is a systematic method aimed at minimizing waste without sacrificing productivity. It focuses on optimizing efficiency and eliminating waste in various areas of production. Here are the areas it typically targets:

A. Customer relations: Improving interactions and satisfaction with customers. B. Supplier networks and factory management: Enhancing efficiency in the supply chain and within factory operations. C. Packaging design: While packaging can be optimized, it is not a primary focus area of lean manufacturing. D. Product design: Streamlining design processes to reduce waste and improve functionality and manufacturability.

Therefore, the correct answer is C: Packaging design.

References:

Womack, J. P., & Jones, D. T. (2003). Lean Thinking: Banish Waste and Create Wealth in Your Corporation. Free Press.

Liker, J. K. (2004). The Toyota Way: 14 Management Principles from the World's Greatest Manufacturer. McGraw-Hill.