Which of the following is a symptom of a chemical attack?

Irritation of the eyes, nose, and throat is a well-known symptom of a chemical attack because many chemical agents can cause immediate and acute reactions upon exposure. For instance, agents like chlorine gas and tear gas (such as CS gas) directly affect mucous membranes, leading to symptoms such as redness, watering eyes, sneezing, coughing, and a burning sensation. These initial reactions are often among the first indicators that a chemical agent has been released, prompting individuals to take protective measures.

Other options may present symptoms that can arise from various medical conditions or environmental factors but are not specifically indicative of a chemical attack. For example, blurred vision and muscle pain could result from many causes not related to chemical exposure, and skin rashes along with fever could suggest allergic reactions or infections. Excessive sweating and chills are similarly nonspecific and could also be attributed to numerous other health issues or stress responses. Therefore, irritation of the eyes, nose, and throat distinctly aligns with the immediate effects associated with chemical weapon exposure.