A nimbostratus cloud is a multi-level, grey, often dark, amorphous, nearly uniform cloud that usually produces continuous rain, snow, or sleet but no lightning or thunder.
Nimbostratus clouds bring continuous precipitation that can last for many hours. These low-level clouds are full of moisture. Cumulonimbus clouds are also called thunderheads. Thunderheads produce rain, thunder, and lightning.
The correct answer is Slovenia. Croatia and Bosnia gained independence later during the nineties after a series of wars, while Slovenia had it relatively easy and was the first.