help please

PC Construct a 90% confidence interval to estimate the population mean using the data below x=21 S= 4.5 n=12 What assumptions need to be made about this population? The 90% confidence interval for the population mean is from a lower limit of 1867 to an upper limit of 23 33 (Round to two decimal places as needed) What assumptions need to be made about this population? A. The population distribution is skewed to one side B. The population follows the Student's t-distribution C. The population follows the normal probability distribution D. The population size is larger than 30