The water content of a soil volume is measured four times gravimetrically by oven drying. The mean value of the water content is 23.2%. If the standard deviation of the four measurements is 1.0%, the 99% confidence interval for the soil water content is most nearly:________.
A. (19.5%, 26.9%)
B. (18.6%, 27.8%)
C. (20.6%, 25.8%)
D. (20.9%, 25.5%)