group column and visualization

Hello community,

I am quite new to PowerBi and have faced the following issue:
there are 4 columns with data entries which may overlap (as shown below).

I need to create a chart which presents as a graph the sumarized information (for example how many people has choosen lidl as first option/second etc, how many have choosen Billa as first/second etc):

How can I do that, as when I do the above chart it is taking the data only from the first column, ignoring the rest.

Thanks in advance

Martin