I need to answer this exercise, and do it with R studio, can you give me the codes and the interpretation in each part, thank you.

9. Consider aus_arrivals , the quarterly number of international visitors to Australia from several countries for the period 1981 Q1 2012 Q3. a. Select one country and describe the time plot. b. What can you learn from the ACF graph? c. What can you learn from the PACE graph? d. Produce plots of the seasonally differenced data (1 B)(1 34)}? What model do these graphs suggest? e. Does ARIMA( ) give the same model that you chose? If not, which model do you think is better? f. Write the model in terms of the backshift operator, then Without using the backshift operator