I would like to gather these arrays into maybe one single array, so that I could use a switch in order to select which question I would like to set up by a trigger later.
I would highly recommend revisiting your data structure.
It looks like all questions follow the same format : one question string and four answer strings. Instead of using a string array, you should probably make a custom structure with 1 string field for the question, and either 4 string fields for answer or an array of answers.
Then instead of making a struct with 20 arrays of strings, simply use an array of your new struct type. The whole thing should become much clearer to manage and use.