Joy Corporation manufactures a product with the following per unit standard costs: Direct Materials 10 square yards at $6 per yard Direct Labor 12 hours at $10 per hour The following information relates to actual operations: Direct materials purchased - 1000 square yards at $5 per yard Direct materials used in production - 900 square yards Direct labor cost = $10,000 Direct labor hours = 1,200 Actual output = 80 units The direct materials quantity variance is: a. $600 favorable b. $600 unfavorable c. $1000 favorable d. $1000 unfavorable.