The best method to obtain a random sample of the employees to be surveyed from the options provided would be:
Selecting every tenth employee that enters the building.
This method ensures that every employee has a chance to be included in the sample, helping to avoid bias and giving a better representation of the entire employee population. The other options either include self-selection (which can lead to bias), focus on a specific group (like nurses or car owners), or only include volunteers, which may not represent the views of all employees.