This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
True about bell's curve is - 
Select and explain. 
A. It skewed to the left, B. Has mean =1[?]0, C. Has standard deviation = 0[?]0, D. Has variance =1[?]0
D: Has variance =1[?]0
Answer: D: Has variance =1[?]0 
Explanation: Ans. is 'd' i.e., Has variance =1.0 Standard normal curve (Bell curve or Gaussian distribution) has been explained in previous sessions.