Which chemical agent is used for harassment and may be combined with lethal agents?

The correct answer is that tear agents are often used for harassment and can be combined with lethal agents. Tear agents are a type of chemical weapon that causes temporary blindness, excessive tearing, and respiratory discomfort. Their primary purpose is to incapacitate individuals without causing permanent harm, making them effective for crowd control or similar scenarios.

While other chemical agents like blister agents and nerve agents can cause severe harm or death, they are typically not used primarily for harassment but rather as lethal or incapacitating agents. The vomiting agent primarily causes disorientation and can disrupt functions, but it is not specifically designed for harassment in the same way tears agents are.

In summary, tear agents stand out as being specifically intended for harassment, offering a temporary means of control, which is why they are the most relevant choice regarding the question.