If a Set of Data Is Approximately Normally Distributed,we Would $\pm$

Multiple Choice

If a set of data is approximately normally distributed,we would find that approximately

A) 2 of every 3 observations would fall between $\pm$ 1 standard deviation around the mean.
B) 4 of every 5 observations would fall between $\pm$ 1.28 standard deviations around the mean.
C) 19 of every 20 observations would fall between $\pm$ 2 standard deviations around the mean.
D) All the above.