Random Samples of Size 81 Are Taken from an Infinite $\surd$

Multiple Choice

Random samples of size 81 are taken from an infinite population whose mean and standard deviation are 45 and 9,respectively.The mean and standard error of the sampling distribution of the sample mean are:

A) 45 and 9
B) 45/81 and 9/81
C) 45 and 9/ $\surd$ 81
D) 45/ $\surd$ 81 and 9/ $\surd$ 81