I booked a flight, and the aircraft is A340-300. However, all seat finding websites (seat guru, seat experts, etc..) don't have the same seat map as shown when I'm trying to pick a seat.

I'm flying at C class. Apparently, it's a 2-class plane, but there isn't any 2-class option for the A340-300. Am I missing something here? Any idea which seats should I avoid in this flight?

Thanks a lot