Answer:
D) All of the above
Step-by-step explanation:
"Fit testing" is important when it comes to respirators. This ensures the respiratory safety of the wearer. When it comes to tight-fitting respirators, a good fit is very important. This means that the respirator will seal to the skin, so it is important not to have any facial hair like beards, mustache, or stubble. OHSA requires that the person should be clean-shaven.
Fit testing is also done annually in order to adjust to any physical changes such as weight gain or dental work. So, all of the choices above can change the fit of the respirator.