The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
The two main defenses you can use in the event of a discriminatory practice allegation are Business necessity and Bonafide Occupation Qualification.
Business necessity. In legal terms, Business necessity means that the company has a justified argument to fire an employee in order to pursue the goals of the company. This is legal resource employers have to support their decisions of laying off employees.
Bonafide Occupation Qualification. This means that there is a valid justification due to gender or age, for not allowing an employee to perform a duty in the workplace. So employers use this Bonafide Occupation Qualification as a legal argument to fire an employee.