Which are correct:

[color=red]1-Assume there is a box full of books, and you have been told the number of the books.

[color=indigo]2-Assume there is a box full of books, the number of which you have been told.

[color=blue]3-Assume there is a box full of books, of which the number you have been told.

[color=darkblue]4-Assume there is a box full of books, whose the number you have been told.

Gratefully,

Navi.