The following information is available for Brownstone Products Company for the month of July: Actual Master Budget Units Sales revenue Variable manufacturing costs Fixed manufacturing costs Variable selling and administrative expenses Fixed selling and administrative expenses 3,700 $57.600 10,200 12,100 6,700 8,200 4,000 $60,000 16,000 13,400 8,000 9,500 Required 1 Compute the July sales volume variance and the flexible-budget variance for the month in terms of both contribution margin and operating income. (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values. ) Flexible-Budget Variance Sales Volume Variance Contribution margin Operating income