Agray-scale digital camera with 1,000,000 pixels takes a picture (the picture is made of 1,000,000 parts and each part has a certain amount of gray). a histogram is made where the data is the amount of gray in each of these parts. the histogram looks bell-shaped with a mean of 125 gray levels and a standard deviation of 15.

approximately how many pixels have a gray scale of between 110 and 140?

a. 30
b. 500,000
c. 680,000
d. 950,000