Ans. is 'a' i.e., Chronic osteomyelitis Clinical features of chronic osteomyelitiso The commonest presenting symptom is a chronic discharging sinus. Pain is minimal or absento Generalized symptoms of acute osteomyelitis are not present except in acute excacerbations.o On examination there is irregular thickening of boneo Mild tenderness may be seen in deep palpationo Adjacent joint may be stiff.Radiological featureso Following are radiological features:-i) Thickening and irregularity of the cortices.ii) Patchy sclerosisiii) Bone cavity: This is seen as an area of rarefaction surrounded by sclerosis.iv) Sequestrum: This appears denser than the surrounding normal bone because the decalcification which occurs in normal bone, does not occur in dead bone. Granulation tissue surrounding the sequestrum gives rise to a radiolucent zone around it. A sequestrum may be visible in soft tissue.v) Involucrum and cloacae may be visible.