Which of the Following Statements Is TRUE Concerning Controllability of Costs

Which of the following statements is TRUE concerning controllability of costs?

A) Fixed costs are controllable costs.
B) Controllable costs are easy to identify with much accuracy.
C) Senior managers rarely differ in their reliance on controllable costs for performance measurement.
D) All costs are controllable, given a sufficiently long time period.
E) Most costs are under the sole influence of any one manager.