Which of the following statements supports the use of longer time periods, such as a year, to calculate indirect cost rates? a. Longer the period, the smaller is the influence of seasonal patterns on the amount of costs. b. Shorter the period, the smaller is the influence of seasonal patterns on the amount of costs. c. Longer the period, the greater is the influence of seasonal patterns on the amount of costs. d. Shorter the period, the greater is the influence of seasonal patterns on the amount of costs