Choose the sentence that correctly uses the 'future perfect continuous' tense.

1. ক
   By next year, I will have been working here for a decade.
   
2. খ
   By next year, I will be working here for a decade.
   
3. গ
   By next year, I will have worked here for a decade.
   
4. ঘ
   By next year, I will work here for a decade.