Which of the following is a symptom of NSP?

The symptoms associated with NSP, or neurotoxic shellfish poisoning, primarily involve neurological effects. Dizziness and incoherent speech are indicative of this condition, as NSP affects the nervous system through the consumption of contaminated shellfish. The toxins involved can disrupt normal brain function, leading to these specific symptoms.

While other options list symptoms that might be present in different health conditions—such as gastrointestinal disturbances or respiratory issues—they do not align with the hallmark neurological signs associated with NSP. In particular, chills and headache are more indicative of other illnesses, while swelling in the throat would suggest an allergic reaction or other acute condition, rather than the specific toxic effects of NSP. Understanding the unique presentation of NSP is crucial for identifying and managing this type of poisoning effectively.