When grendel speaks of urferth and says. i could crush him ike a fly (89) what literary device is being used?

In me thou see'st the glowing of such fire that on the ashes of his youth doth lie, as the deathbed whereon it must expire consumed with that which it was nourished by. which theme do these lines best support? a. all people grow old and die. b. in old age, people grow like a fire. c. flames turn everything to ash d. fire glows and burns