This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Schizophrenia and other psychotic disorders, Subject name: Psychiatry
Folie-a-deux means 
Select and explain. 
A. Delusion of persecution, B. Sharing of delusion, C. Delusion of double, D. None
B: Sharing of delusion
Answer: B: Sharing of delusion 
Explanation: This is an uncommon delusional disorder characterised by a sharing of delusions between usually two ( folie-a-deux) or occasionally more persons ( folie-a-trios, folie-a-quatre, Folie-a-Famille), who usually have a closely knit emotional bond. Only one person usually has authentic delusions due to an underlying psychiatric disorder, most often schizophrenia or delusional disorder. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 85