Preble Company manulectures one product. its variable manufacturing overhead is applied to production based on direct. lebour hours, and its standard costs per unit are as follows. The company planned to produce and sell 21,000 unats in March. However, during March the company actually prodiaced and sold 26.600 units and incurred the following costs: a. Purchased 154,000kg of raw materials at a cost of $9,50 per kg. All of this material was used in production. b. Direct labour 63,000 hours at a rate of $13 per houe. c. Total variable manufacturing oveihesd for the month was $510,930 5. What is the labour rate variance for March? (Indicate the effect of each varinnee by selecting "F" for favorable, "U" for unfovorable, and "None" for no effect (i.e.. zero vorionce.). Do not round intermediote caiculations)