:2. Diagram ? on page ? shows a histogram for the blood pressures of subjects in a certain survey, along with the normal curve which approximates it. The percentage who had blood pressures between 120mm and 140mm is exactly equal to a. 40%

b. the area under the histogram between 120 and 140

c. the area under the normal curve between 120 and 140

d. 100%

e. 0%