Amber is the manager of a popular clothing store. She regularly works over $40$ hours a week; however, when new styles are coming in that require new displays, she may put in as many as $60$ hours a week. Amber's paycheck is the same regardless of the number of hours she has worked. Amber is paid $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.$

Group of answer choices

based on a total compensation arrangement

based on an incentive compensation program

on a wage system

on a salary basis