Which of the following statements can be inferred from the graph ?()
Ⅰ.School X has a smaller enrollment than School Y.
Ⅱ.If the age of a book is the number of years since purchase, then the average (arithmetic mean) age of a book in the School Y inventory is less than that of a book in the School X inventory.
Ⅲ.According to the inventory, School X and School Y purchased the same number of textbooks in 1976.
A.None
B.Ⅰ only
C.Ⅱ only
D.Ⅰ and Ⅱ
E.Ⅱand Ⅲ