Which dark solar feature is shown in the picture above? Solar flare
Prominence
Sunspot
Corona

picture is not given in this answer

sun spots

Explanation:

the under lying reason for the winter war was soviet concern about Nazi Germany's expansionism.  the secret protocol of the pact gave the soviet union a sphere of influence that included Finland, the Baltic States, and and parts of Eastern Europe.  Suomussalmi is considered the the clearest most important and most significant Finnish victory in the northern half of Finland