Confidence interval

An investment has a mean return of 15% and a standard deviation of returns equal to 10%. If the distribution ofreturns is approximately normal, which ofthe following statements is least likely correct? The probability of obtaining a return: A. less than 5% is about 16%. B. greater than 5% is about 84%. C. greater than 35% is about 2.5%. D. between 5% and 25% is about 95%. the correct anwser is D because 95% probability of obtaining a return fall between -4,6% and 34,6% But how to justify other choices if it"s correct???

i asked exctly the same q a while back: Here you go: http://www.analystforum.com/phorums/read.php?11,697387,697622#msg-697622

thank you I will look at your thread

I think the probability of a return between 5 and 25% is 68% since its only std away.