Which agent category includes substances that cause harm or incapacitation to personnel?

The correct choice relates to the classification of substances designed specifically to harm or incapacitate personnel. Antipersonnel agents are intended for use against individuals, adversely affecting their ability to function effectively. These can include a range of materials, from chemical compounds to biological toxins, that are meant to incapacitate enemy combatants or adversaries during conflicts or security operations.

In contrast, biochemical agents refer to harmful biological or chemical substances that can lead to disease or toxic effects. While these agents can also incapacitate, they are typically distinguished by their mechanisms (e.g., infectious agents, toxins). Persuasive agents are actually aimed at influencing or manipulating behavior without direct harm, often seen in psychological operations. Nonlethal agents are designed to incapacitate without causing permanent harm, although they can still lead to adverse effects. Thus, while there are overlaps in the broader category of agent types, the defining purpose of antipersonnel agents is direct harm or incapacitation, making it the most accurate choice.