Hi!
I really need help to read the seats available on myidtravel..

I booked a flight (Lis-ams), the airline is Transavia (ticketless airline), the emotion is green but in "seats available" is saying:

C1 B1 A1 U

What it does mean?

If the emotion stills green, doesnt make sense if the flight is full. Or not?

Thank you!