'I swear through fire and ice to be your humble knight.' Tells us a lot about and itself exemplifies the medieval ideal of chivalry. Knights sweared lojalty to their lord and fouht for them in times when they were needed. That is also exactly what we can observe here; he stated that he would fight for him and swore lojalty to him.
"I swear through fire and ice/To be your humble knight."
Chivalry is the moral code of knights during medieval times. The last option is the best because it demonstrates the loyalty of the knight to his king. It also shows him to be humble which is another trait of chivalry. Being head of the court does not show any moral code, and neither does how his hair looks with the crown. Option C is also not correct because it doesn't say anything about a knight; it only details the behavior of a woman.
Sentence fragments are groups of words that look like sentences, but really aren't. To be a sentence, groups of words need to have at least one independent clause. This however does not have a independent clause.
