This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
The diagnosis of fibromyalgia is made in patients with a history of diffuse musculoskeletal pain and which of the following physical findings: 
Select and explain. 
A. Symmetrical joint tenderness, B. Muscle weakness, C. 11 of 18 tender points, D. Multiple areas of tendonitis
C: 11 of 18 tender points
Answer: C: 11 of 18 tender points 
Explanation: Fibromyalgia is a syndrome of known and probably multifactorial cause, which leads to diffuse musculoskeletal pain. Patients often note fatigue, paraesthesia, subjective swelling, and sleep dismrbance. In general, their physical exam is normal. The have tenderness in at least 11 of 18 proscribed tender areas. It is unknown what these areas represent, but their occurrence and reproducibility have been well-documented.