Which of the following best defines 'Conventional Implicature'?

1. ক
   Implicatures based on the Cooperative Principle
   
2. খ
   Implicatures associated with specific lexical items like 'but' or 'even'
   
3. গ
   Implicatures derived from context alone
   
4. ঘ
   Implicatures that depend on the listener's mood