XYZ Manufacturing produces car parts. The company has a variable cost per unit of $100 and fixed costs of $100,000. The company sells each car part for about $125. Recently, the company is considering increasing its advertising by $50,000 in order to sell more car parts. How many additional parts must the company sell in order to justify the increased advertising costs?
a. 2,000 units
b. 4,000 units
c. 6,000 units
d. Cannot be determined from the information provided.