A manufacturing process produces bags of cookies. The distribution of content weights of these bags is Normal with mean 15.0 oz and standard deviation 1.0 oz. We will randomly select n bags of cookies and weigh the contents of each bag selected. How many bags should be selected so that the standard deviation of the sample mean is 0.1 ounces?
 a. 8 bags
 b. 10 bags
 c. 64 bags
 d. 100 bags