The relevant production range for Challenger Trailers, Inc. is between $100,000$ units and $160,000$ units per month. If the company produces beyond $160,000$ units per month,

A$.$ both the fixed costs and the variable cost per unit may change

B$.$ the fixed costs and the variable cost per unit will not change

C$.$ the fixed costs will remain the same, but the variable cost per unit may change

D$.$ the fixed costs may change, but the variable cost per unit will remain the same