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

<passage>:
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 He had not sought in his mind for the flood's cause, but had merely taken it numbly as part of the fury and confusion of a world in ruin. Anyway, he was dead tired out on his feet. He sensed more than saw the looming wall before him, but he thought ponderous repose across the river valley, its head and tail spilling over the hills on either side, five miles apart. The beast was quiescent until morning—sleeping, if such things slept. 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 scattered black hummocks—crests of knolls like that on which he stood, all soon to be hidden by the rising flood. For a moment he knew despair. The way back was impassable, and the way ahead was blocked by the titanic enemy. Then the impersonal will that had driven him implacably two days and nights without stopping came to his rescue. Westover plodded forward, pressed his shrinking body against the slimy, faintly warm surface of the monster's foot, and sought above him with upstretched hands—found him. The moonlight's fading again was merciful as he climbed the sheer, slippery face of the foot but he could hear the wash and chuckle of the flood below. His tired brain told him treacherously: "I'm already asleep—this is a nightmare." Once, listening to that insidious voice, he slipped and for instants hung dizzily by his hands, and for some minutes after he had found a new foothold merely clung panting with pounding heart. Some time after he had found courage to resume the climb, he dragged himself, gasping and quivering, to comparative safety on the broad steep that rose to the summit of the monster's humped back, a mountain to be climbed. Westover felt poignantly that his exhausted body could not make that ascent and face the long and dangerous descent beyond, which he had to make before dawn ... but not now ... not now.... 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 still fighting, had accumulated quite a store of knowledge about the Westover no longer saw the murky moonlight, the far faint glitter of Westover awoke, feeling himself bathed by the cold sweat of nightmare—then he realized that a misty rain had wetted his face and sogged his clothes. That, and the sleep he had had, refreshed him and made his mind clearer than it had been for days, and he remembered that he could not sleep but had to go on, searching with a hope that would not die for some miraculously spared refuge where civilization and science might yet exist, where there would be the means to realize his idea for stopping the monsters. He sat up, eyes searching the sky for a sign to tell him how long he Even as Westover began frantically climbing, out of that lightening sky the hopelessness of his effort pressed down on him. With dawn the monster would begin to move, to crawl eastward impelled by the same dim knees on the shagreen-roughness of the skin at first he thought only that an attack of dizziness had made him fall, then he realized that kind. But he knew with desperate clarity that by nightfall, when the beast became still once more, exhaustion and growing hunger would have made him unable to descend. As he lay where he had fallen, he felt that weakness creeping over him, no longer held in check by the will that had kept him doggedly plodding forward. Again he lay half conscious, in a lethargy that unchecked must grow steadily deeper until death. Isolated thoughts floated through his material on the world which was their prey.... And men must starve, as he was starving now.... With a struggle Westover roused himself, first sitting up, then swaying to his feet, frowning with the effort to look sanely at the terrible inspiration that had come to him. The cloud blanket was breaking up, the sun already high, beating down on the naked moving plateau on which thing's surface round about. Westover laughed wildly with a sudden hour later was replete. Either the long fast, or involuntary revulsion, or perhaps merely the motion of the creature brought on nausea, but he fought it sternly back and succeeded in keeping his strange meal down. Then he was tormented by thirst. It was some time, though, before he the man could have left it then, but somehow night after night he did not. It wasn't, he argued with himself sometimes in the days when he lay torpidly drowsing, lulled by the long sway, arms over his head to protect him from the sun's baking, merely that he was chained to the only source of food he knew in all the world—not just that he was He woke with the sun's warmth on his body and the realization of something amiss trickling through his head. It was a little while before he recognized the wrongness, and when he did he sat bolt upright. The sun was already up, and the monster should have begun once more its steady, ravenous march to the east. But there was no motion the great living expanse lay still around him. He wondered wildly if it was dead. Presently, though, he felt a faint shuddering and lift beneath his feet, and heard far stifled mutterings and sighs. Westover's mind was beginning to function again it was as though the cessation of the rock and sway had exorcised the lethargy that had lain upon him. He knew now that he had been almost insane for the time he had passed here, touched by the madness that takes hermits and men lost The monster on which Westover had been living as a parasite was That was the meaning of its gargantuan belly rumblings. And they meant further that he must finally leave it—now or never—or be borne aloft that blue headland could be only a land made desert, where men become beasts fought crazily over the last morsels of food. He had lost track Westover sat for a space with head in hands, hearing the faint He had been hearing them again as he awoke—the distant muffled voices faint eructations deep inside the monster. Then he sprang to his feet, gripping his hand-ax, and ran panting to the place where he had dug for food. His excavations tended to close and heal overnight now he went to work with vicious strokes enlarging Westover hesitated. "I'm not just imagining you?" he appealed. Westover was still not sure that the other was more than one of the and Westover nodded this time with alacrity. The crawling descent through the twisting, Stygian burrow had much and Westover climbed to his feet and stood, weak-kneed still, staring 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 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 "Amen," agreed Sutton. But the gaze he fixed on Westover was oddly Westover flexed his hands involuntarily, like one who has been too Westover stared. "Why?" "No! Of course I realize—Well, I see what you mean—I think." Westover Westover bowed his head, but he had caught a curiously expectant glint

<question>:
Why was Westover described as shrinking?

<options>:
A He was starving because the monsters ate all the food
B He was afraid of encountering the monster
C He was a cowardly person
D He was tired from walking a long way

<answer>:

A