A researcher wanted to check whether the BMI of Canadian adults with obesity has increased in 2009 compared to 2005. He used Health Canada data. A randomly selected 27 Canadian adults from 2005 data gave a mean of 26.2 and a standard deviaon of 1.5; A randomly selected 27 Canadian adults from 2009 data gave a mean of 26.6 with a standard deviaon of 1.7. BMI is normally distributed in each year with the same variance. He wants to develop a 99% confidence interval for the change in BMI. Let populaon1 be 2005 data and populaon2 be 2009 data. Write down the crical value: A. 2.403 B. 2.678 C. 2.575 D. 2.33