RTI Company's master budget calls for production and sale of 19,000 units for $91,200, variable costs of $38,000, and fixed costs of $21,000. During the most recent period, the company incurred $33,000 of variable costs to produce and sell 21,000 units for $86,000. During this same period, the company earned $26,000 of operating income. Required: 1. Determine the following for RTI Company: (Do not round intermediate calculations. Round your answers to the nearest whole dollar.) a. Flexible-budget operating income. b. Flexible-budget variance, in terms of contribution margin. Was this variance favorable (F) or unfavorable (U)? c. Flexible-budget variance, in terms of operating income. Was this variance favorable (F) or unfavorable (U)? d. Sales volume variance, in terms of contribution margin. Was this variance favorable (F) or unfavorable (U)? e. Sales volume variance, in terms of operating income. Was this variance favorable (F) or unfavorable (U)? a. Flexible-budget operating income b Flexible-budget variance C. Flexible-budget variance d. Sales volume variance . Sales volume variance