Which of the following is one of the controversial points with manufacturing overhead ?: Select one:

a. They generally have a single cost cause, which makes it easy to calculate an indirect cost allocation rate.

b. There are fluctuations in the level of activity as well as in the indirect cost itself

c. At the time of requiring to compute an indirect cost rate, you have all the information necessary to do so

d. They are easy to link and measure with the product