单选题 Construct a 90 percent confidence interval for the starting salaries of 100 recently hired employees with average starting salaries of $ 50000 and a standard deviation of $ 3000 assuming the population has a normal distribution.

• A. 50000±1.65 (3000);
• B. 50000±1.65 (300).
• C. 30000±1.65 (5000).