trouver le bon pronom relatif (il n y a pas de "that")

Clue 1 is the code ...... only mr Somoyer knows
Clue 2 is the literary genre ..... Mr Lemat likes
Clue 3 is the writer ..... best book is Sherlock Holmes
Clue 4 is the number....... is the answer to all questions
Clue 5 is the spell ........... you can ask Mrs Druze
Clue 6 is ....... Mrs Verget likes to ses Pi​