Which symptom is least likely to be associated with mononucleosis?

The correct choice is persistent coughing, as it is typically not a common symptom associated with mononucleosis. Mononucleosis, often caused by the Epstein-Barr virus, primarily presents with symptoms related to systemic viral infections such as fatigue, fever, sore throat, and lymphadenopathy.

Malaise is very common among individuals with mononucleosis, reflecting the overall feeling of illness and fatigue that often accompanies viral infections. Stiff neck can occur as a result of lymph node swelling and discomfort in the neck region, and while it is not classic, it can happen in cases where lymphatic involvement causes muscle strain or irritation. Nausea may occasionally occur, but it is typically not as prevalent or defining as the other symptoms.

In contrast, a persistent cough is more characteristic of respiratory conditions rather than mononucleosis, which focuses more on systemic symptoms rather than isolated respiratory issues. Therefore, recognizing the symptoms that are central to the disease helps in understanding what is least linked to mononucleosis.