Which of the following is/are true?

A. The average of given data is less than the greatest observation and greater than the smallest observation of the given data.

B. If the observations of a given data are equal, then the average of the data may or may not be same as the observations.

C. If all the observations of a given data get increased by x, then their average is also increased by x.

D. If all the observations of a given data are divided by x, then their average may or may not change.

Choose the most appropriate answer from the options given below: