Which of the following statements concerning the use of support department and joint cost allocations for performance evaluations is not true? Oa. It is rare to need further investigation beyond a preliminary analysis when a manager misses a performance target. Ob. A manager may miss a performance target because direct materials costs are too high. O c. A manager may not be responsible for the allocation of support department costs if he or she cannot control the square footage of the areas upon which cost allocations are based. Od. A manager may miss a performance target because he or she has no control over the joint processes prior to his or her department which is after the split-off point.