Concept:A synonym is a word having the same or nearly the same meaning as another word.
Explanation:"Skirmish" means a small, short fight or a brief conflict.
"Hassle" means an annoying or troublesome situation, often involving a minor argument or conflict.
So, "Hassle" is the closest synonym among the choices.
The other options relate to peace or agreement:
"Concord" means harmony, "Truce" and "Armistice" both mean agreements to stop fighting.
Therefore, these are not synonyms of "Skirmish".
Answer:C. Hassle