Which chemical agent can cause copious amounts of tears?

CS, or tear gas, is a chemical agent specifically designed to induce tearing and irritation of the eyes, leading to copious amounts of tears. It is widely utilized in crowd control and law enforcement situations due to its effectiveness in temporarily incapacitating individuals without causing permanent harm. CS works by targeting the mucous membranes in the eyes, nose, and throat, leading to the immediate production of tears as a response to the intense irritation.

The potency and rapid onset of CS's effects make it a preferred agent over other chemicals for situations requiring crowd management and dispersal. While other agents listed may also cause discomfort or other reactions, it is the unique property of CS to elicit an overwhelming tearing response that differentiates it as the correct answer.