Group A and B are only populated if the post “work in process” to the ledger is selected.
Group C and D record the actual cost of the finished goods and the actual cost of raw material used in production because group A and B are used to record the estimated costs and are fully reversed at the ending of production.
You also need to decide if you post this way, you can alter this in the production parameters.
I suggest you set this up and walk through the process and look at the postings.