Which of the following conditions is characterized by weakness, fever, and enlarged lymph nodes?

Mononucleosis is the condition characterized by weakness, fever, and enlarged lymph nodes. This illness, often caused by the Epstein-Barr virus (EBV), leads to a variety of symptoms that make it recognizable. The combination of extreme fatigue, fever, and significant swelling of the lymph nodes in the neck and armpits aligns well with the clinical picture of mononucleosis.

The presence of these symptoms occurs because the infection triggers an immune response, causing the lymphatic system to become activated. The resultant lymphadenopathy (swollen lymph nodes), alongside systemic symptoms such as fever and profound fatigue, are hallmark signs that distinguish mononucleosis from other infectious diseases.

In the context of the other conditions listed, while infections like Chlamydia and Gonorrhea can present with certain systemic symptoms, they typically manifest with more localized symptoms, particularly in the reproductive or urinary tracts, rather than the generalized symptoms associated with mononucleosis. Syphilis, depending on the stage, can cause a variety of symptoms, but the classic presentation of weakness, fever, and lymphadenopathy is most closely associated with mononucleosis. Hence, the portrayal of mononucleosis aligns precisely with the symptoms described in the question