1. In this context, fickle means B. inconsistent. It means that the subject is unpredictable, capricious, unstable, so she can't sustain any of her friendships. Affectionate means friendly and caring; loyal means faithful and true; rude means impolite, blunt, insulting.
2. Sentinel means D. protector. Confidant means close friend, crony, intimate person, which a dog cannot be. Adversary is the opposite of that - enemy, opponent, contestant, rival. Vigilante is a person who takes the law into their own hands, because they are not satisfied with the official law enforcement.
3. Grendel easily killed thirty warriors during his first attack because his victims were B. asleep. That night, after getting drunk, they fell asleep. It was easy for monstrous Grendel to sneak in, grab thirty of them, and drag them into his hide-out at the moor, to eat them.
4. I believe the correct answer is D. It describes supernatural monsters. From antiquity, epic poems have always dealt with non-realistic, supernatural daemons. In Beowulf's case, those daemons are Grendel and his mother. By defeating them, the protagonist, that is the hero, shows qualities that differentiate him from common people.
5. I believe the right answer is A. loyalty. They escorted him to the lake, and are now waiting for the battle to occur under water. In essence, Beowulf is the only person who could possibly defeat the female monster, as he had already defeated and killed her son. All his warriors can do is wait for him and help him, if possible. They keep waiting for him even after they see blood coming from the lake.
6. The Geats carry Grendel's heavy head all the way to Heorot out of pride. This head is a symbol of the final victory of good over evil. When Beowulf killed Grendel, the evil wasn't exterminated, as his mother was still living. But now that she is also dead, the terrorizing of Hrothgar's people and the disruption of his realm's peace is finally over.
