The management of Elaka Air, an airline company, has set a mandatory retirement age for its flight attendants. This is because the management strongly feels that with age, flight attendants find it difficult to work in a pressurized cabin for extended periods. In the context of federal employment laws, this scenario exemplifies a(n) _____.

A. registered employment agreement
B. bona fide occupational qualification
C. critical skills employment permit
D. employment regulation order