Answer:
d. 40%
Step-by-step explanation:
The formula to compute the contribution margin is shown below:
Contribution margin = (Contribution ÷ sales) × 100
= ($72,000 ÷ $180,000) × 100
= 0.4 × 100
= 40%
The other items which are mentioned in the question are not relevant. Hence, it is not considered in the computation part.
And, the contribution margin should always be calculated on sales value.