Great idea! It would be nice if the country could be a "hidden answer component" so when the capital has been guessed, the country will appear beside it.
To do that you will need to make a "Hint" column of their corresponding countries. After adding that hint column to Step 3 - Manual Quiz Design, go one by one and click on each hint. Click on the "Answer Component" box and change it to "Answer component - hidden" for every country.