A couple of refinements:
* The file includes a row for each problem-answer combination that actually occurred.  So for a choice problem that has five possible choices but only four that are observed, the file includes four rows.  
* Multiple choice problems in CAPA means that the user can select more than one choice, in contrast to choice problems.  So if there are five possible choices offered, then the total number of possible answers is 2^5 (or 2^5 -1 if something must be selected).  
* The table below uses 'variant' and the text above uses 'variation'.  
* It might be good to describe more about variants -- that it doesn't actually enumerate the actual variation in the problem content displayed, but enumerates the possible variation.  We don't actually check whether any use is made of randomization, but if it's set for the problem, we tabulate the answers separately for each variant.
* In order to reinforce that the variant is the problem's variant (not an answer variant), I suggest changing word order to:   problem, variant, and answer.  Or parallel earlier text with "problem-variant-answer combination".