The Mean Systolic Blood Pressure for a Random Sample of 28

The mean systolic blood pressure for a random sample of 28 women aged 18-24 is 114.9 mm Hg and the standard deviation is 13.1 mm Hg. Construct a 90% confidence interval for the standard deviation ?, of the systolic blood pressures of all women aged 18-24. Round to the nearest hundredth when necessary.

A) (10.22, 18.34)
B) (10.75, 16.94)
C) (11.23, 15.99)
D) (10.59, 16.54)