The average age of residents in the large residential retirement community is 69 years with the standard deviation 5.8 years. A simple random sample of 100 residents is to be chosen, and the sample mean age of these residents is to be computed.
The probability that the average age, mean , of the 100 residents chosen is less than 68.5 years is
A. 0.805.
B. 0.568.
C. 0.195.
D. 0.043.