A random sample of 50 bottles is selected from the production line of a large manufacturing company. The mean weight of the contents of the 50 bottles is 20.25 ounces. The manager of the company requests that the machines be recalibrated because bottles coming off the production line are supposed to contain 20 ounces. Which of the following statements is true?

The population is the production line that needs to be recalibrated and the sample is all production lines.

The population is all production lines and the sample is the production line that needs to be recalibrated.

The population is all bottles in the production line and the sample is the 50 bottles that were selected.

The population is the 50 bottles that were selected and the population is all bottles in the production line.