Which of the following is a drawback in using a single plantwide rate to apply overhead to product costs?

a. Too much emphasis is placed on the fact that manufacturing processes differ from one product to another.

b. Some overhead costs are missing from the application process.

c. A single driver is used for all overhead costs and it is unlikely that the driver selected is appropriate for every type of overhead.

d. Support department costs are not combined with all other overhead costs.