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 has high infectivity, D. Virus yields has high Hemagglutination low infectivity', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Virus yields has high Hemagglutination low infectivityIncomplete viruses: Due to defect during assembly of viral components, some of the daughter virions that are produced may not be infective. Example of such incomplete virus is the influenza virus that shows a high Hemagglutination titer but with a low infectivity. This is known as von Magnus phenomenon.", 'role': 'assistant'}]