Earliest sign indicative of sacroilitis on X ray is?

Ans. is 'c' i.e., Blurring of SI joint * Radiographically, the earliest sign of sacroiliitis is indistinctness of the joint The joints initially widen before they narrow.Radiographic Sacroiliitis grading (New York criteria)i) Grade 0: normalii) Grade 1: some blurring of the joint margins - suspiciousiii) Grade 2: minimal sclerosis with some erosioniv) Grade 3a) Definite sclerosis on both sides of jointb) Severe erosions with widening of joint space with or without ankylosisv) Grade 4: complete ankylosis