DR Congo is an odd one. Why not put Korea (Democratic People's Republic of Korea) as it starts with D too? How about Democratic Republic of São Tomé and Príncipe or Democratic Socialist Republic of Sri Lanka? Then there's Democratic Republic of Timor-Leste. I would suggest leaving Congo out or including these states.
All of the other names you listed are the former, official names of these countries, which we don't often use in daily life or on JetPunk. However, Democratic Republic of the Congo is the short, official long term and short term for the country, as to avoid confusion with the Republic of the Congo. If it was listed as Congo, Democratic Republic of , this require editing other JetPunk quizzes and changing the criteria that has already been set in place by the Quizmaster.