At the entrances of most gardens, usually there are （） to serve as screens that conveniently restrict one’s vision. Which of the following is not included?

At the entrances of most gardens, usually there are （） to serve as screens that conveniently restrict one’s vision. Which of the following is not included?
A.some rockeries
B.small courtyards
C.tracery windows
D.pavilions
正确答案：pavilions