PPC shifts from increased resources or productivity, not utilization

Steps:

• PPC shows maximum output combinations with full resource use and given technology.
• Outward shift to PPC2 requires more resources, better technology, or higher productivity.
• Option A improves use of existing labor, moving along PPC1.
• Options B, C, D expand effective resources or skills, shifting to PPC2.

Why A is correct:

• PPC assumes full employment; increasing employment from underutilization moves along the curve, per standard economic definition, without altering production capacity.

Why the others are wrong:

• B: Raises labor supply by extending workforce participation, adding resources.
• C: Enhances human capital, boosting productivity and potential output.
• D: Increases capital stock, expanding overall production capacity.

Final answer: A