Chronic Fatigue Syndrome (CFS) is the widespread name for a disorder that is also called Myalgic Encephalomyelitis (ME), but many sufferers object to the name CFS on grounds that it is does not reflect the severity of the illness. While profound fatigue is one symptom of this debilitating condition, there are many others, including muscle pain, headaches, and cognitive difficulties. Its nomenclature is not the only controversial aspect of CFS. Although an estimated 17 million people worldwide have CFS, its cause is unknown and a diagnostic test does not exist. Doctors must first rule out other conditions that share CFSs symptoms. As there is no cure for CFS, treatment tends to focus on alleviating symptoms, which can range from mild to severe. Despite the World Health Organisation classifying CFS as a neurological disease, there is much disagreement within the medical community. Some scientists believe that CFS originates from a virus, others argue that it stems from genetic predisposition, while still others believe that it is a psychiatric condition. Because of continuing scepticism about CFS, patients welcomed a 2009 study that linked CFS and a XMRV retrovirus. What at first appeared to be a major scientific breakthrough, however, was not proven by further research  and XMRV is now thought to be a lab contaminant.
Question: CFS is a severely debilitating condition for 17 million people worldwide
Options:
A. true
B. false
C. uncertain
Answer: C