A medical center conducted a study to investigate cholesterol levels in people who have had heart attacks. A random sample of 16 people was obtained from the names of all patients of the medical center who had a heart attack in the previous year. Of the people in the sample, the mean cholesterol level was 264.70 milligrams per deciliter (me/dL) with standard deviation 42.12 mg/dL. Assuming all conditions for inference were met, which of the following is a 90 percent confidence interval for the mean cholesterol level, in mg/dL, of all patients of the medical center who had a heart attack in the previous year? 
选项为:A:(242.26, 287.14)  B:(244.06, 285.34)  C:(246.24, 283.16)  D:(247.38, 282.02)  E:(260.09, 269.31)  请回答其中一个选项.