Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
STRANGE EXODUS Gigantic, mindless, the Monsters had come out of Westover got a shock when he stumbled onto the monster, for all that he knew one had been through here. He had been following the high ground toward the hills, alternately splashing through waist-deep water and climbing onto comparatively dry knolls. To right and left of him was the sullen noise of the river in flood, and behind him, too, the rising water he had barely escaped. The He had not sought in his mind for the flood's cause, but had merely He sensed more than saw the looming wall before him, but he thought He recoiled as if seared, and retreated, slithering in the muck. For the monster's body had formed an Westover stood motionless in the blackness how long, he did not know. He was hardly aware of the water that covered his feet, crept over his ankles, and swirled halfway to his knees. Only the emergence of the moon through a rift of the cloud blanket brought him awake its dim light gleamed all around on a great sheet of water, unbroken save for scattered black hummocks—crests of knolls like that on which he stood, all soon to be hidden by the rising flood. nights without stopping came to his rescue. Westover plodded forward, the monster's foot, and sought above him with upstretched hands—found steep that rose to the summit of the monster's humped back, a mountain He lay in a state between waking and dreaming, high on the monster's side and it seemed that the colossal body moved, swelling and sighing—but he knew they did not breathe as backboned animals do. Westover had been one of the men who, in the days when humanity was Westover no longer saw the murky moonlight, the far faint glitter of below, and beneath the black cloud something that writhed and flowed structure, the monsters have attained their great size and perhaps for "The monsters who have descended on Earth must represent the end result of a long evolution completed in space itself. They are evidently deep-space beings, able to propel themselves from planet to planet and monsters have finished with Earth, there will be no vegetation left all devoured by the monsters." Westover awoke, feeling himself bathed by the cold sweat of idea for stopping the monsters. Even as Westover began frantically climbing, out of that lightening monster would begin to move, to crawl eastward impelled by the same dim beyond the Arctic circle, or aboard ships at sea. The hordes that still lived and wandered over the once populous fertile lands, like For a man like Westover, who had been a scientist, it was not the human pride, the star-storming pride of mind and will—defeated by He could stay where he was unharmed, of course. On the monster's back, weakness creeping over him, no longer held in check by the will that laboratory on the monster's back. Of course the rolling motion would prediction had been a hundred percent correct. The monsters' hunger thing's surface round about. Westover laughed wildly with a sudden miles-long beast twitch like a flea-bitten dog. like a flea, he had lodged on a larger animal and Sutton make that the monsters, extraterrestrial though they were, were in the basic chemistry of proteins, fats and carbohydrates one with man or the amoeba, and therefore might be—food. His matches were dry in their water-proof case fire from the loose fibrous scale of the monster's back, and half an on a dog. The monster crawled by day and rested by night Westover's mind was beginning to function again monster's vitals, and in a flash of insight knew them for what they that had been killed by atomic bombs, the answer to the riddle of and that could be expelled to drive the monster in flight like a reaction engine. Rocket propulsion, of course, was nothing new to zoology it was developed ages before man, by the squids and by those odd degenerate relatives of the vertebrates that are called tunicates because of their gaudy cellulose-plastic armor.... The monster on which Westover had been living as a parasite was stood looking about and what he saw brought him to the brink of despair. For all around lay blue water, waves dancing and glinting in the fresh breeze of the sea. While he slept the monster had crept beyond the coast fathoms. Back the way it had come, a headland was visible, mockingly, hopelessly distant. Of course—the great beast would crawl into the sea, which would float its bloated bulk and enable it to accelerate and take flight. It would never have been able to lift itself into the air from the dry land. He should have foreseen that and made his escape in time. Now that of the days he had been on the monster's back, but the rape of Earth Westover sat for a space with head in hands, hearing the faint faint eructations deep inside the monster. behind. He whirled, for there could be no shadows on the monster's back. "Who are you?" asked Westover, breathlessly but almost without surprise. Westover hesitated. "I'm not just imagining you?" he appealed. Westover was still not sure that the other was more than one of the When, a few hundred yards nearer the monster's head, the other halted into utter blackness—Westover knew that both the Preacher and his own and Westover nodded this time with alacrity. that ought to belong to a journey into Hell.... More than that, no demonologist's imagination could have conceived without experiencing and Westover climbed to his feet and stood, weak-kneed still, staring at a chamber carved in the veritable belly of Leviathan. The floor "It's working," the other answered without looking up from the adjustment he was making. Bubbles were rising in the fluid that filled the trays, rising and bursting, rising and bursting with a curiously told Westover better than words that there was something hugely he and Westover froze in dumbfounded recognition. quick eyes studied Westover's face, and he gestured toward a packing "I stumbled onto it," Westover admitted. "I was wandering across Westover finished the brief account of his coming to dwell on the "I haven't got so far with the theory," said Westover, "but I think from the beginning. But the monsters absorbed into themselves all the source—the monsters themselves. "The monsters almost defeated us, because of their two special "It is inhabitable?" Westover's question reflected no doubt. Sutton gestured at the bubbling device behind him. "That thing is making air now, which we're going to need when the monster's in space. It was when we were still trying to find a poison for the beasts that I running by tapping the monster's internal gas pressure. There are monster is so much like us in fundamental makeup that its body contains "Then," Westover glanced appreciatively around, "it looks like the main hazard is claustrophobia." "Don't worry about a cave-in. We're surrounded by solid cystoid children's—as parasites inside this monster and whatever others we can you mentioned—your monster-killing scheme." Westover flexed his hands involuntarily, like one who has been too from an endoparasite's point of vantage, merely by isolating from Westover stared. "Why?" "No! Of course I realize—Well, I see what you mean—I think." Westover "Your idea is dangerous for the same reason. The monsters probably during that time they'll be living exclusively on their fat—the fuel they stored on Westover bowed his head, but he had caught a curiously expectant glint Eventually, the monsters will come to another planet not too unlike Earth, because it's on such worlds they prey. A tapeworm can cross the Sahara desert in the intestine of a camel—"

<question>:
What is not something Westover discovers about the monsters in this passage?

<options>:
A They can be a food source
B They can be killed by administering a specific type of cut near their head
C They can produce fuel which lets them fly
D They can float on water

<answer>:

B