Answer:
B. Contribution margin per unit will decrease and contribution margin ratio will not change
Explanation:
The formula to compute the contribution margin per unit and the contribution margin ratio is shown below:
The Contribution margin per unit = Selling price per unit - Variable expense per unit
And, the Contribution margin ratio = (Contribution margin per unit) ÷ (selling price per unit) × 100
Let us assume that the selling price per unit is $100
And, the variable expense per unit is $50
So, the contribution margin per unit is $50
The contribution margin ratio = $50 ÷ $100 = 50%
Now if the selling price and variable expenses both decrease by 5%
So, the new selling price per unit is $95
And, the new variable expense per unit is $47.5
So, the contribution margin ratio = $47.5 ÷ $95 = 50%
Hence, the correct option is B.