31 Which of the following statements correctly describes the difference between a master budget and a flexible budget? 41.00 P@ ; a. The master budget is established before the period begins for planning purposes, and the flexible budget is established after the period ends for control and evaluation b. The master budget is established before the period begins for planning purposes, and the flexible budget is established before the period ends because of GAAP requirements. O c. The master budget is established after the period ends for planning purposes, and the flexible budget is established before the period begins for control and evaluation Od. The master budget is established before the period begins for control and evaluation, and the flexible budget is established after the period ends for planning purposes