Read the line from grendel.

i was safe in my tree, and the men who fought were nothing to me, except of course that they talked in something akin to my language, which meant that we were, incredibly, related.

this is an example of a

first-person narrative showing grendel’s perspective.
first-person narrative showing beowulf’s perspective.
third-person narrative showing many perspectives.
third-person narrative showing grendel’s and beowulf’s perspectives.

First of all, since there is a word "I" in the excerpt, it means that it is first person perspective, given that the person who is speaking is describing what is happening before his very eyes. If it were third person, it would say "she" or "he" or a name.
Second of all, you can see that the person who is talking is an outsider who cares nothing for the people before him, which we know is definitely not characteristic of Beowulf, but of the monster, Grendel.
Thus, the correct answer is that this is an example of first person narrative showing Grendel's perspective. 

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