Which symptom is described as the worst headache of a person's life?

The symptom described as "the worst headache of a person's life" is typically associated with a subarachnoid hemorrhage. This type of headache is characterized by its sudden onset and severe intensity, often being described as a "thunderclap" headache. Patients may experience this headache with little to no prior warning, and it is often accompanied by other symptoms such as nausea, vomiting, neck stiffness, or changes in consciousness due to the irritation of the meninges and increase in intracranial pressure caused by the blood in the subarachnoid space.

In contrast, migraines, tension headaches, and cluster headaches present differently. Migraines can be severe but usually develop gradually and are often associated with features like nausea, vomiting, and photophobia. Tension headaches tend to be milder and may present with a tight band-like sensation around the head, while cluster headaches are intense but typically recurrent in clusters and occur in cyclical patterns. These differ in presentation and intensity compared to the acute and severe nature of a headache due to subarachnoid hemorrhage. Therefore, the defining characteristic of the worst headache of a person's life distinctly points to subarachnoid hemorrhage as the correct answer.