Supply Curve Shifters vs. Demand Factors

Steps:

• Recall that supply curve shifts from changes affecting producers' costs, technology, taxes, or subsidies, not consumer-side factors.
• Evaluate A: Producers' costs directly impact production expenses, shifting supply left or right.
• Evaluate B: Fuel price affects car owners' operating costs, influencing demand, not supply.
• Evaluate C and D: Taxes and wages alter producers' net costs, shifting supply; B does not.

Why B is correct:

• Per supply-demand law, only producer-side changes (e.g., input costs) shift the supply curve; consumer fuel costs shift demand by changing buyer willingness to pay.

Why the others are wrong:

• A: Raises/lowers production costs, shifting supply curve.
• C: Alters producers' after-tax revenue, shifting supply.
• D: Increases labor costs for producers, shifting supply left.

Final answer: B