A 75 year old woman has neck pains. Her cervical X rays confirm atlanto axial subluxation

A 75 year old woman has neck pains. Her cervical X rays confirm atlanto axial subluxation. Which one of the following conditions is most likely to be associated?
A. Rheumatoid arthritis
B. Wegener’s granulomatosis
C. Marfan’s syndrome
D. Multiple sclerosis
E. Syringomyelia