A. 1. A homogeneous relationship between the individual cost items in the dependent variable cost pool and the cost driver(s) does not exist. 2. The relationship between the cost and the cost driver is not stationary. B. 1. The time period used to measure the dependent variable is not properly matched with the time period used to measure the cost driver(s). 2. Fixed costs are allocated as if they are variable. C. 1. Data are either not available for all observations or are not uniformly reliable. 2. Extreme values of observations occur. D. All of the above are correct