There are altogether eleven books on the shelf, ______ five are mine.[ ]

A. on which

B. in which

C. of which

D. from which

井下防爆电气设备引入电缆须采用压盘式或压紧螺母式引入装置，必须具有防松与防止电缆拔脱的措施；电缆引入装置应（）（）（）（）。