Hi there! I feel that C.) would be the best answer for this question. Fighting in a war wouldn't show that you value the culture of your homeland, like shown in answer A.). B and D seem irrelevant to the question at hand, and since the language of a country relates directly to the culture and answer C.) shows that Juhan values it, it'd be safest to go with that answer.
All of the above, these are all reasons why people do research! Hope this helps!
