Complete each sentence with who, which or where

1. Look! Can you see the boy over there
   [who|which|where] is wearing a fantastic black hat? This is our new student.
2. I forgot the name of a cafe
   [who|which|where] I liked a lot last week.
3. The book
   [who|which|where] I've given you is from the library. I need to take it back.
4. Can we go to the same hotel
   [who|which|where] we stayed last winter holiday?
5. I know all the pictures of I.Levitan
   [who|which|where] is my favourite artist.
6. Oh, no! I can't find the parking place
   [who|which|where] I've put my car.