The correct answer is A. Battle-sweat
Step-by-step explanation:
In language, a kenning refers to a set of words or expression that has a metaphorical or deep meaning. Kennings are commonly used in literature for aesthetical purposes and most of them derived from Old-English. Additionally, most kennings are composed of two or more words hyphenated that express one single concept or idea. According to this, the one that is a kenning is "battle-sweat" because this includes two hyphenated words that have a metaphorical meaning as "battle-sweat" is used to refer to "blood" as this liquid is common in battles.