In Which of the Following Instances Is Disparate Treatment Considered

In which of the following instances is disparate treatment considered legal?

A) In a particular retail outlet, male workers are employed to handle the sales.
B) In an electrical company, male workers are exclusively employed to work as electricians.
C) In a vehicle manufacturing company, male workers are exclusively employed in all departments.
D) In a certain shopping mall, female workers are exclusively employed to clean the ladies restroom.
E) In a particular hospital, only female nurses are appointed.