ex a
1 who /2 where / 3 (which) / 4 who / 5 whose / 6 (which) / 7 which / 8 whose / 9 where / 10 who / 11 (who) / 12 where
ex b
3 which, 6 which, 11 who could be left out
ex c
3 Beijing, which is one of the world's biggest cities, hosted the 2008 Olympic Games.
4 Michael Jackson's Thriller, which was released in 1982, was one of the best-selling albums of the 80s.
6 Sally and Joe, who got married last year, are expecting their first baby.
