The president of a company wants to know about how many of the office chairs in the building need to be replaced. which sampling method will result in a sample that is not biased?

she puts notices in the break rooms asking employees to e-mail her about the condition of their chairs.

she inspects every chair in the sales department.

she gives a list of employee names to the maintenance supervisor and tells him to inspect the chair of every fifth employee.

she asks every other employee she sees in the cafeteria about his chair.