The number of column inches of classified advertisements appearing on Mondays in a certain daily newspaper has mean 320 inches and standard deviation 30 inches. Suppose that the results for 100 consecutive Mondays can be regarded as a random sample and let denote the mean number of column inches of classified advertisements in the sample. Assuming a sample of 100 is sufficiently large, the random variable has
A. a sampling distribution that has a mean of 3.2 inches.
B. a sampling distribution that is approximately Normal by the central limit theorem.
C. a sampling distribution that has a standard deviation of 3 inches.
D. All of the above