Assume the price of an item is normally distributed in a certain city. We randomly sample three shops in the city selling the item at $25, $24, and $26. Which of the followings...

Assume the price of an item is normally distributed in a certain city. We randomly sample three shops in the city selling the item at $25, $24, and $26. Which of the followings gives 100(1−α)%-confidence interval for the mean price of the item throughout the city?