Assume that Nortel manufactures specialty electronic circuitry though a unique photoelectric process. One of the primary products, Model ZX40, has a standard labor time of 0.5 hour and a standard labor rate of $13.50 per hour. During February, the following activities pertaining to direct labor for ZX40 were recorded: Direct labor hours used- 2,180 Direct labor cost- $34,000 Units of ZX40 manufactured- 4,600 Please show all work a. Determine the labor rate variance b. Determine the labor efficiency variance c. Determine the total flexible budget labor cost variance