The answer is: A.Healthful
A workplace would be categorized as 'healthful' if it is designed to ensure the health and wellness of the people that work on the site.
In united states, all of the safety requirement in the workplace is being overlooked by an organization called Occupational Safety and Health Administration. They create list of requirements that must be followed by employers and conduct daily investigation to ensure that all workplaces that operate maintain a healthful standard.