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

<passage>:
QUEST OF THIG Thig of Ortha was the vanguard of the conquering "HORDE." He had blasted across trackless space to subdue a defenseless world—only to meet on Earth emotions that were more deadly than weapons. rod-like weapon of white metal and his pouches for food and specimens. The Orthan entered the narrow strip of trees and crossed to the little-used highway on the other side. Here he patiently sat down to wait for an Earthman or an Earthwoman to pass. His task now was to cruiser where his two fellows and himself would drain the creature's mentality of all its knowledge. In this way they could learn whether a planet was suited for colonization by later swarms of Orthans. Already they had charted over a hundred celestial bodies but of them all only three had proven worthy of consideration. This latest planet, metal at the reflection of himself! The Earthman was opposite now and he must waste no more precious time. The mighty muscles of the Orthan sent him hurtling across the intervening space in two prodigious bounds, and his hands clamped across the mouth and neck of the stranger.... wears he might be Thig." "Thig will be this creature!" announced Torp. "With a psychic relay we will transfer the Earthman's memories and meager store of knowledge to the brain of Thig! He can then go out and scout this world without "Do not question the word of your commander," growled Torp, swelling their love-life, their everything! So it was that the bodies of the Earthman and the Orthan were strapped on two parallel tables of chill metal and the twin helmets, linked to dry of knowledge. The shock upon the nervous system of the Earthman proved too violent and his heart faltered after a time and stopped completely. Twice, with subtle drugs they restored pseudo-life to his Earth-creatures were hugging at his legs. An odd sensation, that his acquired memories labeled as pleasure, sent a warm glow upward from around his heart. chaos of his cool Orthan brain. Tonight or tomorrow night at the latest he must contact his two fellows and report that Earth was a planetary paradise. No other world, including Ortha, was so well-favored and rich. An expeditionary force to wipe the grotesque civilizations of Earth out of existence would, of course, be necessary before the first units of new Hordes could be imperfect though their civilization might be, to make room for the Hordes? Thig tried to tell himself that it was the transmitted thoughts of the dead Earthman that made him feel so, but he was not too sure. For three months he had lived with people who loved, hated, wept and sacrificed for reasons that he had never known existed. He had learned the heady thought the same thoughts that a governor might think. Uncertainty added zest to every day's life. The Orthan had come to question the sole devotion of the individual to the Horde to the exclusion of all other interests. What, he wondered, would one new world—or a hundred—populated by the Hordes add to the progress of humanity? For a hundred thousand years the Orthan Thig groaned. He was a weakling to let sentimentality so get the better sapping the life from his own brain. He knew that the story would never be written, but he toyed with the idea. So far had Thig the emotionless, robot-being from Ortha drifted from the unquestioning worship of the Horde! Ortha at once. "I will recommend the conquest of this planet, 72-P-3 at once and the complete destruction of all biped life upon it. The mental aberrations of the barbaric natives might lead to endless complications if they were permitted to exist outside our ordered way of life. I imagine that "But why," asked Thig slowly, "could we not disarm all the natives and degree of knowledge and comfort?" "Only the good of the Horde matters!" shouted Torp angrily. "Shall a race of feeble-witted beasts, such as these Earthmen, stand in the way of a superior race? We want their world, and so we will take it. The "Never again do I wish to set foot upon the soil of this mad planet. There are forces at work upon Earth that we of Ortha have long forgotten." words are highly irrational. Some form of fever perhaps native to this world. While you examine him I will blast off for Ortha." broad fingers bit deep into the unyielding metal of his chair. Suddenly he knew that he must go back to Earth, back to Ellen and the children of the man he had helped destroy. He loved Ellen, and nothing must stand between them! The Hordes of Ortha must find some other world, an empty world—this planet was not for them. "Turn back!" he cried wildly. "I must go back to Earth. There is a woman there, helpless and alone, who needs me! The Horde does not need this planet." the Orthan's vital throat tubes. His fingers and thumb gouged deep into Kam's startled throat and choked off any cry for assistance before it could be uttered. for long moments they swayed there, locked together in silent deadly struggle. The fate of a world hung in the balance as Kam's other hand fought against that lone arm of Thig. corruption that swiftly gave way to hardened blobs of dessicated matter. Horror for what he had done—that he had slain one of his own Horde—made his limbs move woodenly. All of his thoughts were dulled Even Torp, thought Thig ruefully, gave way to the primitive rage of his ancestors at times but to that very bit of unconscious atavism he now owed his life. A cool-headed robot of an Orthan would have efficiently used the blaster to destroy any possibility of remaining life in his unconscious body. The deadly attack of Thig his own violent avenging of Kam's death, and now the apparent return of the man he had killed come to life had all served to jolt his rigidly trained brain from its accustomed groove. The shock had been too much for the established thought-processes of the Orthan. the skeleton-thing that had been Torp, using the new strength that victory had given him to drive him along. He had saved a world's civilization from extinction! The thought sobered him yet, somehow, he was pleased that he had done so. After all, it had been the Earthwoman and the children he had been thinking of while he battled Kam, a selfish desire to protect them all. He went to the desk where Torp had been writing in the ship's log and read the last few nervously scrawled lines: Planet 72-P-3 unfit for colonization. Some pernicious disease that strikes at the brain centers and causes violent insanity is existent there. Thig, just returned from a survey of the planet, went mad and destroyed Kam. In turn I was forced to slay him. But it is not ended. planet Ortha. Unless a rogue asteroid or a comet crossed the ship's path she would return safely to Ortha with that mute warning of danger on 72-P-3. The body of Torp would help to confirm his final message. regret in his mind that he was not returning to the planet of his first existence. He thought of the dull greys and blacks of his planet, of the crowded his mind. He shivered suddenly, remembering his utter callousness the first time he had sent a space ship whipping down toward the hills and valleys below. And there was a sickness within him when he fully realized that, despite his acquired memory and traits, he was an alien from outer space. He fingered the tiny scars that had completely obliterated the slight heaved a gasp of relief. He was no longer Thig, a creature of a Horde's now, for the rest of his life, he must make up to the dead man's family. The knowledge that Ellen's love was not really meant for him would be

<question>:
Why does Thig change his mind about the invasion?

<options>:
A He remembers Ellen and the love he felt, and doesn't want to leave.
B He has forgotten why he lives for the Hord.
C He contracted a disease while on Earth that's making him make wild decisions.
D He is fearful that Earth's influence will affect the Orthan as it did him.

<answer>:

A