Well, sorry for that little digression. Back to the puzzle - there's still the Golf to identify.
I haven't got a picture to help with it, but I found mention of a model called the Rinspeed Topaz. I don't know if it was ever a production model, but there was a prototype shown at Geneva in 1982, with a diesel engine fitted with a Brown Boveri Comprex forced-induction system. It's described as having a special body built by Rinspeed, with a hatchback opening down to the level of the back bumper, a fixed roof over the rear seats, with fixed rear windows, and a removable Targa roof over the front seats. Could that be car B?