Validating statements on supply-demand equilibrium

Steps:

• Locate equilibrium at intersection of supply (upward-sloping) and demand (downward-sloping) curves at price OP.
• Measure quantities at OP: quantity supplied (QS) along supply curve, quantity demanded (QD) along demand curve; QS = QD at equilibrium.
• Evaluate A: UV traces horizontal distance to supply curve at OP, equaling QS.
• Evaluate B: PX traces horizontal distance to demand curve at OP, equaling QD.
• Evaluate C: At lower price OQ, QD rises (law of demand), but QS falls (law of supply); incomplete phrasing implies erroneous equality to "extra" (likely supplied), which mismatches.
• Evaluate D: OP is where QS = QD, defining equilibrium price.

Why C is correct:

• C violates law of supply: price drop from OP to OQ reduces QS, so new QD exceeds change in QS, not equals "extra."

Why the others are wrong:

• A correctly identifies QS measurement at equilibrium.
• B correctly identifies QD measurement at equilibrium.
• D correctly states equilibrium definition.

Final answer: C