Answer: b. Remain constant
Explanation:
Fixed costs as the term implies, do not change depending on the units produced or sold but rather remain constant over the period. If the company sells 2,000 or 5,000 more units, the fixed costs will remain constant.
For instance, if the rent of the selling warehouse is $4,000 per month and the company stores and then sells any number of units, they will still pay $4,000 regardless.