For products with slow-moving demand—for example, one unit per week—the Poisson distribution is likely to be a better model for demand than the normal distribution because (choose the best answer) 

a. The Poisson’s standard deviation is equal to the square root of its mean. 

b. The normal distribution does not allow the freedom to choose any standard deviation for any given mean. 

c. The Poisson distribution is a continuous distribution. 

d. Only the standard normal distribution would apply in this setting. 

e. The Poisson distribution does not assign any probability to negative outcomes.