Four graphs of different data sets are shown. Which data set has the greatest standard deviation? A. The graph of data set A shows 50 on the horizontal axis, has a normal symmetrical bell curve and the highest frequency is represented by a dashed line at 50. B. The graph of data set B shows 50 on the horizontal axis, has a wide symmetrical bell curve and the highest frequency is represented by a dashed line at 50. C. The graph of data set C shows 50 on the horizontal axis, has a symmetrical bell curve and the highest frequency is represented by a dashed line which is to the right of 50. D. The graph of data set D shows 50 on the horizontal axis, has a symmetrical bell curve and the highest frequency is represented by a dashed line which is to the left of 50.