This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Area under mean +/- 2 SD will include ------------% of population. 
Select and explain. 
A. 99%, B. 95%, C. 68%, D. 50%
B: 95%
Answer: B: 95% 
Explanation: (Refer: K. Park’s Textbook of Preventive and Social medicine, 24th edition, pg no:886 )
Normal distribution

Gaussian / Standard distribution
Symmetric with respect to same mean, median & mode & frequencies tapers off rapidly and symmetrically on both sides