Insufficient data for exact calculation Steps:

• August contribution per unit: $40 -$12 = $28; total contribution: 6000 ×$28 = $168,000 (assumes fixed costs unchanged).
• September selling price: $40 × 0.9 =$36; contribution per unit: $36 -$12 = $24.
• Required units: $168,000 ÷$24 = 7000 (not in options). Not enough information to match choices, as fixed costs or other details appear missing/ambiguous.

Final answer: Not enough information.