Her bag, ________ she put all her books, has not been found.

1. A.
   in which
2. B.
   at which
3. C.
   in that
4. D.
   into which

Her bag, ________ she put all her books, has not been found.

[　　]

Her bag, ________ she put all her books, has not been found.

[　　]