Which of the following is not true about cost allocation? Select one: a. When a noninsulating allocation base is used to allocate common costs, the allocation base will not fluctuate with other subunits performance. b. Noninsulating cost allocations can reduce the risk managers bear. c. Whenever interaction is unimportant, common costs should be allocated using a base that does not insulate subunits. d. Insulating allocations cause one managers performance to be distorted by another managers performance.