The production manager of a company was experiencing a high defect rate on the assembly line, which was slowing production and causing wastage of valuable direct materials. The production purchased a higher grade of materials that would be more reliable , but was worried that the cost of the new materials might negatively affect operating income. This would produce a _______

A. Unfavorable direct materials cost variance

B. Favorable direct labor cost variance

C. Unfavorable direct materials efficiency variance

D. Favorable direct labor efficiency variance