correct is D, what working out do you need to get to this

Voldemort Enterprises manufactures a product. The product has costs that are 50% variable, 50% fixed. If production this year is expected to be 10% higher than last year, this production volume is within the relevant range, and the underlying costs of production does not change, this year the average total cost per unit will: Remain unchanged ered Increase The extent of any change cannot be determined swer Decrease