need help with this problem:

Construct a 99% confidence interval to estimate the population mean using the accompanying data. What assumptions need to be made to construct this interval? x = 52 o=12 n=15 What assumptions need to be made to construct this interval? O A. The population is skewed to one side. O B. The population mean will be in the confidence interval. O C. The sample size is less than 30 O D. The population must be normally distributed. With 99% confidence, when n = 15, the population mean is between the lower limit of and the upper limit of (Type an integer or decimal rounded to two decimal places as needed.)