A company has a significantly varied product and service mix, with many high-volume, homogeneous products and many low-volume, complex products. Historically, the company has used a single, company-wide overhead rate. After implementing an activity-based costing system, company is likely to find?

a. The high-volume products were under-costed previously.

b. The high-volume products were over-costed previously.

c. The low-volume products were over-costed previously.

d. The costs of both low- and high-volume products will be unchanged.