This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': "In scurvy, all the following radiological signs are seen except - \nSelect and explain. \nA. Pelican spur, B. Soap bubble appearance, C. Zone of demarcation near epiphysis, D. Frenkel's line", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Radiological features of scurvy\n\nThe typical radiological features occur at the ends of long bones, particularly around the knee, i.e. lower end of the femur and upper end of the tibia. Other common site is the proximal end of the humerus.\nFeatures are\xa0-\nGround glass appearance of bone\nPencil thin cortex\nWhite line of Fraenkel\xa0→\xa0represents well-calcified cartilage in the metaphysis.\nOsteoporosis gives ground glass appearance.\nWimburger sign\xa0→\xa0white ring surrounding the epiphyseal centres of ossification.\nZone of rarefaction under the white line\xa0→\xa0represents a linear break in the bone, proximal and parallel to white\nline and epiphyseal separation may occur along this line.\nLateral part of this rarefaction is seen as a triangular defect.\nPelkan spur or lateral spur\xa0→\xa0lateral prolongation of the white line.\nDuring the healing phase, subperiosteal hemorrhages becomes calcified and the affected bone assumes a dumbbell or club shape.', 'role': 'assistant'}]