Detailed Answer
Answer (B) is correct. Not all variances are directly caused by the managers. Some of these variances can be beyond the control of the manager. Thus, identifying the manager who is responsible for not achieving desired results should not be the main reason for why variances are calculated. If responsibility for certain costs exceeds the extent to which a manager can influence or control that activity, the result may be reduced morale, a decline in managerial effort, and poor performance. This is known as the concept of controllability.