please explain why for each answer

QUESTION 15 Which of the following is true about managers who adhere to the concept of "management by exception"? Managers will investigate only favorable variances. Managers will investigate only variances that are significant. a. ob. . Managers will investigate all favorable and unfavorable variances. Managers will investigate only unfavorable variances. od. QUESTION 16 Actual sales rarely match budgeted sales in the master budget. True False QUESTION 17 During the control phase, organizations are most concerned about getting accurate estimates that lead to positive results True False