1. Assume researchers are trying to find out the mean concentration levels of a specific drug in a population of individuals' blood during a clinical trail. The researchers find that the sample population of 40 has a mean concentration of 7.1 mcg/mL with a standard deviation of 1.7 mcg/mL. Calculate a 95% confidence interval for the mean concentration level of the medication for the population's blood and interpret it.

A) The researchers are 95.0% confident the true mean concentration of medication in the population's blood is between 6.573 mcg/mL and 7.627 mcg/mL.

B) The researchers are 95.0% confident the true mean concentration of medication in the population's blood is between 6.235 mcg/mL and 7.165 mcg/mL.

C) The researchers are 95.0% confident the true mean concentration of medication in the population's blood is between 4.568 mcg/mL and 8.832 mcg/mL.

D) The researchers are 95.0% confident the true mean concentration of medication in the population's blood is between 4.5615 mcg/mL and 8.8385 mcg/mL.

Please provide answer an explanation.