Which factor(s) is/are most likely a potential cause(s) of multiple sclerosis (MS)?

A. MS is believed to be an autoimmune disorder where the immune system attacks the myelin sheath, but it is not simply a hypersensitivity reaction. B. Current evidence suggests that a combination of environmental factors (such as viral infections, vitamin D deficiency) and genetic predisposition contribute to the development of MS. C. Allergic responses to antiviral medications are not linked to causing MS. D. MS is not caused by a bacterial infection of the myelin; it is an autoimmune demyelinating disease.