A national manufacturer of unattached garages discovered that the distribution of the lengths of time it takes two construction workers to erect the Red Barn model is normally distributed with a mean of 36 hours and a standard deviation of 5 hours. What percent of the garages take between 36 and 40 hours to erect?
A. 3.94%
B. 21.19%
C. 78.81%
D. 28.81%