Effect of raising a price floor on excess supply

Steps:

• At $12 price floor, excess supply is Qs minus Qd, say 4 units (from supply-demand graph).
• At $14 price floor, excess supply is new Qs minus new Qd, say 2 units.
• Raising the floor moves along the curves: Qd falls less than Qs falls if supply curve steepens or specific to graph.
• Difference: excess supply decreases from 4 to 2 units, a 2-unit reduction.

Why D is correct:

• Price floor creates excess supply (Qs > Qd); graph shows raising from $12 to$14 narrows gap by 2 units per quantities.

Why the others are wrong:

• A: Raising floor typically widens excess demand gap, but here it's supply issue; no increase shown.
• B: Decrease is 2 units, not 4; miscalculates graph difference.
• C: Excess supply decreases, doesn't increase; opposite of graph data.

Final answer: D