Which of the following agents can neutralize unpleasant odors?

The correct answer is deodorizers, which are specifically designed to neutralize or eliminate unpleasant odors rather than simply masking them. Deodorizers work by chemically interacting with the odor molecules, thereby neutralizing the smell and leaving the space smelling fresh. They can contain various active ingredients such as enzymes, fragrances, or essential oils that directly target and neutralize the sources of odors.

In contrast, masking agents are formulated to cover up the unpleasant odors rather than eliminate them. While they may provide a temporary scent that is more pleasant, they do not address the underlying cause of the odor.

Oxidizers are generally utilized for their ability to break down certain substances but are not specifically designed to neutralize odors in a carpet cleaning context. Descalers, on the other hand, are used primarily for removing mineral deposits and typically would not have any effect on odors. Therefore, the effectiveness of deodorizers makes them the appropriate choice for neutralizing unpleasant odors.