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
According to ICD 10, the symptoms of schizophrenia should persist for how long for its diagnosis? 
Select and explain. 
A. 2 months, B. 1 month, C. 6 months, D. 2 weeks
B: 1 month
Answer: B: 1 month 
Explanation: According to recent ICD 10, It is 1 month and according to DSM 5 it is 6 months to diagnose schizophrenia Ref: Essentials of postgraduate psychiatry By JN Vyas 1st ed Pg 365