Masking or _________ agents are used to cover a malodor with a stronger more pleasant odor.

The correct answer is aromatic agents. These substances are specifically designed to mask unpleasant odors by introducing a stronger, more pleasant scent. In carpet cleaning and odor control, aromatic agents play a key role in effectively combating malodors by providing an immediate and often lasting fragrance that can help to neutralize the unpleasant smell. This is particularly important in environments such as homes, offices, or businesses where odors can be distracting or off-putting.

Time release agents, which you mentioned as your choice, typically refer to products engineered to slowly release their active ingredients over time. While they may be used for various purposes including scent release, they do not specifically refer to the action of simply covering up a malodor immediately with a stronger scent as aromatic agents do. Understanding the role of aromatic agents in odor control can significantly enhance the effectiveness of carpet cleaning and maintenance efforts.