Choice "D" is correct. The purchasing manager is directly involved in the negotiation of materials prices and would have the greatest influence over the direct materials price variance. The direct materials price variance could be used to monitor purchasing manager performance.Choice "c" is incorrect. The direct materials quantity variance relates to the amount of materials used and would be influenced most significantly by the production manager.Choice "a" is incorrect. The direct labor rate variance is associated with compensation paid to the direct labor force. A human resource or other professional tasked with recruiting and hiring direct labor would have greater influence on this variance than the purchasing manager.Choice "b" is incorrect. The direct labor efficiency variance would largely be under the control of the production manager, not the purchasing manager.