Change the sentence 'Seeing the police, the thief ran away' into a compound sentence.

1. ক
   The thief saw the police and ran away.
   
2. খ
   When the thief saw the police, he ran away.
   
3. গ
   The thief saw the police, so he ran away.
   
4. ঘ
   The thief ran away because he saw the police.