RTI Company$$s master budget calls for production and sale of $18,800$ units for $$95,880,$ variable costs of $$41,360,$ and fixed costs of $$20,800.$ During the most recent period, the company incurred $$32,800$ of variable costs to produce and sell $20,800$ units for $$85,800.$ During this same period, the company earned $$25,800$ 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 or unfavorable?

c$.$ Flexible budget variance, in terms of operating income. Was this variance favorable or unfavorable?

d$.$ Sales volume variance, in terms of contribution margin. Was this variance favorable or unfavorable?

e$.$ Sales volume variance, in terms of operating income. Was this variance favorable or unfavorable?