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D) between 6.05 and 8.33
This is because 99.7% of values lie within 3 standard deviations of the mean in a bell-shaped distribution. So, approximately 99.7% of apple diameters lie between 7.19 - (3*0.38) and 7.19 + (3*0.38), which is between 6.05 and 8.33.