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: Surgery
[{'content': 'Which of the following shows lowest frequency of cleft\nlip and palate? \nSelect and explain. \nA. Negroes, B. Afghanese, C. American Indian, D. Indian', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The incidence of cleft lip and palate is 1:600 live births and of isolated cleft palate is 1:1000 live births. The incidence increases\xa0 in\xa0 Oriental\xa0 groups\xa0 (1:500)\xa0 and\xa0 decreases\xa0 in\xa0 the black\xa0 population\xa0 (1:2000).\xa0 The\xa0 highest\xa0 incidence\xa0 reported for cleft lip and palate occurs in the Indian tribes of Montana, USA (1:276).\nAlthough cleft lip and palate is an extremely diverse and variable\xa0 congenital\xa0 abnormality,\xa0 several\xa0 distinct\xa0 subgroups exist, namely cleft lip with/without cleft palate (CL/P), cleft palate (CP) alone and submucous cleft palate (SMCP).\n\nThe typical distribution of cleft types is:\n\nCleft lip alone: 15%;\nCleft lip and palate: 45%;\nIsolated cleft palate: 40%.\n\nCleft lip/palate predominates in males, whereas cleft palate alone appears to be more common in females. In unilateral cleft lip the deformity affects the left side in 60% of cases.\nKey Concept:\nThe incidence increases\xa0 in\xa0 Oriental\xa0 groups\xa0 (1:500)\xa0 and\xa0 decreases\xa0 in\xa0 the black\xa0 population\xa0(1:2000).\xa0The\xa0 highest\xa0 incidence\xa0 reported for cleft lip and palate occurs in the Indian tribes of Montana, USA (1:276).\nReference: Bailey & Love’s short practice of surgery , 27th\xa0 ed page no 688', 'role': 'assistant'}]