This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sex Intersexuality, Subject name: Gynaecology & Obstetrics
[{'content': 'Delayed puberty is defined if menstruation does not occur by: \nSelect and explain. \nA. 13 years, B. 14 years, C. 15 years, D. 16 years', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is d, i.e. 16 yearsRef: Williams gynae 3rd/ed, p329This is a controversial questionWilliams gynae 3rd/ed, p329 says"Puberty is considered delayed if no secondary sexual characteristics are noted by age 13 or if menses have not commenced by age 16"As per Medicine uptodate - delayed puberty is if mensturation does not begin by 15 years of ageBut its better to go with Williams Gynae.', 'role': 'assistant'}]