As Rafael mentioned, this is a complex problem.
If you want to keep the current data structure, I think you would have to create 4 new calculated columns, [total_A],[total_B],[total_C],[total_D], and for each one you’d have to manually count each score column with an expression like:
IFS( [col1] = "A" , 1)
+
IFS( [col2] = "A" , 1)
+
.....
Then you can chart these 4 new columns on a bar chart.
That’s a mess of work.
Another option would be to create a new Table with a single column just holding A,B,C,D in 4 separate records. Then change all of your Enum columns to Enum base-type of Ref pointing to the new Table. Then create a new column in the first Table that just adds all question columns into a List:
LIST( [col1] , [col2] , … )
Make this new column a List base-type Ref. This will create an “inline” View. You can create a chart view on the new table, pie chart type, showing the single column. Set it to ref position, and it should display as the inline view in the main table’s records.
A further option would be to completely change your data structure. Instead of having 1 column per each question, have a child table that is a single question per records. Creating the chart on this child table would be very straight forward, just like creating the pie chart from option 2.
https://help.appsheet.com/en/articles/961426-references-between-tables