Rank products by contribution per unit of limiting resource (labor hours) Steps: - Calculate variable cost per unit: material + labor (3 hours × $2/hour =$6 for all). - Compute contribution margin: X ($40 -$18 - $6 =$16), Y ($48 -$24 - $6 =$18), Z ($72 -$30 - $6 =$36). - Since labor shortage limits production and all require 3 hours/unit, rank by contribution per labor hour: Z ($36/3 =$12), Y ($18/3 =$6), X ($16/3 ≈$5.33). - Produce in order of highest contribution per hour: Z, then Y, then X. Why D is correct: - D (Z Y X) maximizes total contribution under labor constraint, as it prioritizes products yielding highest profit per scarce labor hour (throughput accounting principle). Why the others are wrong: - A (Y Z X): Starts with lower contribution per hour (Y at $6) before Z ($12), wasting limited labor. - B (X Y Z): Begins with lowest (X at $5.33), delaying higher-return Z and Y. - C (Z X Y): Follows Z with X ($5.33) …