Question: A researcher collected data on systolic blood pressure (SBP) from a sample of hypertensive patients. Sample mean of the measurements was 140.1 mmHg and sample standard deviation was 10.3 mmHg. Only ONE of the intervals presented below can be a 95% confidence interval for the unknown mean SBP of the population. Please, circle this interval and briefly justify your answer.

a) (120.0, 160.0) b) (120.1, 139.1) c) (138.5, 141.7)