Answer:
a). Air separation plant
Step-by-step explanation:
The purifier is a device that removes the pollutants or air contaminants from air to improve the air quality in a given space.
There are basically two techniques or ways by which the air purifier makes the air contaminants free. This two techniques are active and passive.
Active air purifiers : negatively charged ions are released to the atmosphere which sticks the pollutants to the surface.
Passive air purifiers : They use air filters to eliminate pollutants and are more efficient than an active air purifiers.