Alberta Manufacturing Company manufactures a single product. The standard cost of one unit of this product is: During the month of October, 6,000 units were produced. Selected cost data relating to the month's production follow: There was no beginning inventory of raw materials. The variable overhead rate is based on direct labor-hours. Required: a) Compute direct materials price and quantity variances. b) Compute direct labor rate and efficiency variances c) Compute variable overhead spending variance for the month, and prove the efficiency variance given above is currect