Rank by contribution per labor hour

Steps:

• Calculate labor cost per unit: X $4 (0.5×$8), Y $16 (2×$8), Z $20 (2.5×$8).
• Compute contribution per unit: X $10 ($18–$8 total variable), Y$14 ($35–$21), Z $25 ($50–$25).
• Determine contribution per labor hour: X $20 ($10/0.5), Y $7 ($14/2), Z $10 ($25/2.5).
• Rank descending: X ($20), Z ($10), Y ($7) for maximum profit.

Why D is correct:

• Prioritizing highest contribution per limiting factor (labor hour) follows throughput accounting principle to optimize scarce resource use.

Why the others are wrong:

• A: Starts with lowest per-hour contribution (Y at $7), minimizing profit.
• B: Identical to D (likely a listing error), but assumes distinct; otherwise invalid.
• C: Ranks Z ($10) over X ($20), underutilizing highest-yield labor.

Final answer: D