Tricky & Tricky Inc. makes and sells a lawn fertilizer called Supergrow. The company has developed standard costs for one bag of Supergrow as follows Standard Standard Quantity Cost per Bag Direct Materials 20 kilograms $8.00 Direct Labour 0.1 hours 1.10 Variable Manufacturing Overhead 0.1 hours 40 The company had no beginning inventories of any kind on January 1. Variable manufacturing overhead is applied to production on the basis of direct labour hours. The results of the company's operations during January are as follows: Production of Supergrow: 4,000 bags Direct Materials Purchased 85,000 kilograms at a cost of $32,300 Direct Labour Used 390 hours at a cost of $4,875 Variable Manufacturing Overhead Incurred $1,475 Inventory of Direct Materials on January 31 3,000 kilograms a. What was the materials price variance for January? b. What was the materials quantity variance for January? c. What was the labour rate variance for January? d. What was the labour efficiency variance for January