Correct Answer – B
The `Ca^(2+)` ions are arranged in (ccp) arrangement i.e. `Ca^(2+)` ions are present at all corners and tat the centre of each face of the cube, the fluoride ions occupy all the tetrahedral sites. This is 8:4 arrangement i.e., each `Ca^(2+)` ion is surrounded by `8F^(-)` ions and each `F^(-)` ion by four `Ca^(2+)` ions.

Correct Answer – B
`Ca^(2+)` ion is contact with eight `F^(-)` ions and `F^(-)` ion and is in contact with four `Ca^(2+)` ions