What symptom is most commonly associated with a ruptured cerebral aneurysm?

A ruptured cerebral aneurysm is most commonly associated with a sudden severe headache, often described as a "thunderclap headache" or the worst headache of one’s life. This intense headache generally occurs abruptly and is typically a result of blood leaking into the subarachnoid space, causing irritation and inflammation of the meninges and surrounding tissues. The sudden onset and severity of the headache are distinguishing characteristics that set it apart from other symptoms.

In the context of the other options, while confusion, nausea, and fever can be symptoms linked to various neurological conditions or complications following a ruptured aneurysm, they are not as definitive or characteristic as the sudden severe headache. Confusion may arise from increased intracranial pressure or neurological complications, nausea could be a reaction to pain or other underlying issues, and fever may indicate an infection or response to irritation. However, none of these symptoms match the striking immediacy and severity of the headache experienced in the event of a rupture.