Originally Posted by
levitation
It means that the airline has 4 seats to sell in each of the fare buckets. C, J, D are the fare buckets for Business class. In QR C is the most flexible and D the most restricted business class fare.
It also means that you will have plenty of empty seats on your flight and you can move around if you do not like the seat you are in, or at least have the seat next to you empty!

Thank you very much for the explanation. I am looking very forward to my flight tomorrow night.