A male patient of 50 yrs, on routine imaging gets ankylosis in continous 3-4 lumbar vertebrae

A male patient of 50 yrs, on routine imaging gets ankylosis in continous 3-4 lumbar vertebrae with ossification of anterior longitudinal ligament,his sacroiliac joints are normal,Provisional being-

a.Atypical Ankylosing Spondylitis
b.DISH
c.Ochronosis
d.osteoarthritis