The correct answer is B. He is cruel. Grendel is introduced as a bloodthirsty, evil monster. He is a lonely creature who seeks an understanding of the seemingly meaningless world around him. He kills men consistently in the town's mead-hall, ripping them apart. Grendel is shown as evil because he kills passionately.
An author or writer uses his counterclaim as his refutation because a counterclaim is literally what it says. What the writer or author is going against in his writing and which side he is opposing or going with.
The answer is that they both can go without drinking water, hopefully this was helpful