C. German forces failed to break the French lines after nearly 10 months of fighting.
Explanation:
The battle of Verdun was between the German Empire and France, and therefore rules out A.
Weather conditions, trench systems, as well as strategic tactical offensive failures led to slow progress, and Verdun was not captured, ruling out B.
While Britain and France was able to push back against Germany, they were not able to advance into Germany. The war continued to drag on, so it is not D.
Your correct answer would be nativism as that is the political policy that people native to a country are more important than those who are moving here from another country. let me know if you have any further questions :)
