This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Measures of Central Tendency and Distribution, Subject name: Social & Preventive Medicine
All are true about normal response curve except: 
Select and explain. 
A. Bell shaped, B. Total area of curve=l, C. SD = 0, D. Mean, mode, median coincide
C: SD = 0
Answer: C: SD = 0 
Explanation: Ans: C (SD=0) Ref: Textbook of Preventive and Social Mediciner K Park,21st edition feb 2011.page no:788.Explanation:The standard normal curve : smooth,bell shaped.perfectly symmetrical curve (based on infinitely large number of observations).Total area of curve=lMean=0SD=1Mean, median and mode all coincides.