By default, answers to the Country question type use the country's two-character ISO code. You can toggle an option to force those answers to be the country's full name by navigating to the question's configuration (cogwheel icon) and toggling on "Capture full country name".
Gotchas
When using the Country question type within logic on your form, if the default setting is enabled, you will need to use the two-character ISO code. If you have toggled on "Capture full country name" then you must use the full country name.