This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'Von Magnus phenomenon? \nSelect and explain. \nA. Is a normal replicative cycle, B. Virus yield has low hemagglutination, C. Virus high infectivity, D. Virus yields has high hemagglutination titre but low infectivity', 'role': 'user'}, {'content': "Answer: D \nExplanation: When passaged serially in eggs,using as inocula undiluted infected allantoic fluid,the progeny virus will show high hemagglutinin titres ,but low infectivity. This has been called the Von Magnus Phenomenon and is due to the formation of incomplete virus paicles lacking nucleic acid. REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO.500", 'role': 'assistant'}]