Multiple columns to a single column

Hello and thanks in advance,

I've been provided a data set that I need to rearrange for statistical analysis. Columns represent responses from a single person to a questionnaire. Rows represent each question. I've deleted the questions and redacted any names, etc.. There are 9 columns in my attachment although the full data set from one file has approximately 50 columns.

For statistical purposes I need to convert all the columns to a single column of data. I basically need to cut the data column B and paste it directly under column A, and so on. I can do this one column at a time but I have approximately 50 columns in each file and I have about 5 files. Hopefully you can see my need for some easier way to do this and if I attached the file incorrectly feel free to verbally flog me.

Thank you in advance. ....... Rhett