The correct answer is technician A.
A respiratory-protective equipment is used to protect the wearer against inhalation of hazardous substances in the workplace air. It covers the nose and mouth or sometimes the entire face. Respirators may be air purifying, tight fitting, or loose fitting. We should wear respirators only when adequate control of exposure cannot be achieved through other means. A gas mask on the other hand, is made up of light material like paper and does not offer higher level protection than respirator.