Albertville uses a standard cost system for each of its refineries. For the Louisiana refinery, the monthly fixed overhead budget is $8,000 for a planned output of 5,000 barrels. For September, the actual fixed cost was $8,750 for 5,100 barrels. The fixed overhead flexible (spending) budget variance is: O a. $ 875 F O b.$1,500 F O c. $ 750 U O d. $ 800 U