Within the Text Mining tool, you have the ability to create categories which you can then apply to individual responses.
Once you have already created a category that you would like to use, scroll down to the table where all of your open-ended responses are listed. For each response, a "Category" field will be provided. To start adding categories to a response, click on the "+" icon provided for the Category field:
A new window will appear showing the list of categories that have already been created. Select the categories that you would like to add to this response, and click the "Apply" button to save these selections:
You can view all categories that have been assigned to individual responses by viewing the items listed within the "Category" field for these responses: