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

<passage>:
Never had Mars seen such men as these, for they came from black space, carrying weird weapons—to fight for a race of which they had never heard. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Ro moved cautiously. He knew the jungles of Mars well, knew the dangers, the swift death that could come to an unwary traveler. Many times he had seen fellow Martians die by the razor fangs of Gin, the swamp snake. Their clear red skin had become blotched and purple, their eyeballs popped, their faces swollen by the poison that raced through Mars were not to be taken casually, no matter how light in heart one Ro was returning from the north. He had seen the great villages of For a long moment Ro studied the approaching creatures. Then he gasped Ro exclaimed his surprise, then his rage. His handsome face was grim as furry face and twitching tail. The Oan, however, was too intent on his prey to notice Ro at first, and when he did, it was too late. For the young Martian had let fly with the round stone he carried. The Oan squealed in terror and tried to swerve from his course. The fear of one who sees approaching death was in his movements and his eyes were wet with gladness. Warm tears ran down Ro's arm. Finally Na lifted her beautiful head. She looked timidly at Ro, her face a mask of respect. The young Martian tried to be stern in meeting her gaze, as was the custom among the men of his tribe when dealing with women but he smiled instead. woman with golden hair, and the other, a man of age, with hair like silver frost. "There was a great feast then, and our men showed their skill at Ro groaned aloud as Na finished her tale. His homecoming was a meeting Ro squared his shoulders and set his jaw. He wiped a hint of tears from "Then there will be more to kill," answered Ro without turning. Together we will fight the rat men." Na smiled. Ro was angry, but anger did not make him blind. He would make a good mate. but Ro could make out four prone figures. They appeared to "You say they came from a place called Earth?" Ro asked Na in wonder. "All men will know now that you are the mate of Ro," he whispered. And armpit and moved on. Suddenly he halted. A dim figure approached. It was one of the Oan, a guard. He was coming straight at Ro. The young Martian shrank back. Like a phantom, Ro arose from his crouch. The rat man was startled, frozen with fear. Ro drove his right arm around. The stone in his hand Breathing more easily, Ro moved on. He reached the edge of the small Ro was more confident as he moved to untie the others. He worked more When they were ready, Ro signaled the four white people to follow him. something to one of the men. Ro turned and glared at her through the shadows. The progress they made was slow, but gradually the distance between Ro's body tensed and quivered. A low growl issued from deep in his The Oan saw him coming and straightened, allowing the girl to fall. He set his twisted legs and bared his fangs. The fur on his back stood out straight as he prepared to meet the young Martian's attack. Ro struck his foe head on. They went down in a frenzied bundle of fury. The rat man's tail lashed out to twist around Ro's neck. With frantic strength, Ro tore it away before it could tighten. Ignoring the Oan's slashing teeth, the young Martian pounded heavy fists into his soft stomach. Suddenly shifting his attack, Ro wrapped his legs around the rat man's waist. His hands caught a furry throat and tightened. Over and over they rolled. The Oan clawed urgently at the Martian's choking fingers. His chest made strange noises as it pleaded for the air that would give it life. But Ro's hands were bands of steel, Ro dismounted the limp body. His face wore a wildly triumphant smiled as she recognized Ro. The young Martian breathed a sigh of relief. Na turned her head and saw the body of the rat man. She shuddered. When she had recovered from her shock, the small group traveled on. Ro "But there are only six of us," one of the white men protested. "There are hundreds of the beasts. We wouldn't have a chance." Ro smiled. the white ones. The man with the silver hair seemed very old and weak, but very wise. The other men had hair as black as any Martian's, but their skin was pure white. They were handsome, Ro thought, in a barbaric sort of way. One was lean and determined, the other, equally determined, but stouter and less impressive. Ro then centered his attention on the girl. Her introduction—"and myself are an expedition. We came here to Mars to Ro introduced himself and Na. Ro sighed. "I am afraid we are very backward here on Mars," he said wearily. "I Ro awakened with the dawn. He was startled to find that Na had left his Mars, and clusters of wild berries and grapes. "You see," she said, "I will make you a good mate. Our table will be well provided for." "You will make no mate at all," Ro said sternly, "and there will be no The others in the cave awakened. Ro noticed that Charlotte had slept beside Carlson, but moved away shyly now that it was daylight. He noticed, too, that Grimm was seeing the same thing and seemed annoyed. Ro smiled. These young white men were no different than Martians where a girl was concerned. When they had finished breakfast, they sat around the floor of the cave Ro sprang to his feet to tower above the man. His handsome face was twisted in anger. than the Oan." Grimm climbed to his feet and backed away. Ro advanced on him, his The old man also rose. He placed a restraining hand on Ro's arm. "He's lying," said Ro with his thoughts. Ro turned quickly. Ro fell silent. He walked to the mouth of the cave and stared out. When He repeated his plan to the others. "But they'll kill her," gasped Charlotte. "She will be a woman alone," said Ro. "The Oan prefer to capture women when they can." "Then she'll be captured," the professor said. "It's much too risky." Ro laughed. When they had detailed their plan, the party left the cave. Ro led them "We leave you here," said Ro to the professor. "Na will lead you to the Ro looked at Na for a long moment before they parted. He grew very "Come on," Ro said. "If we spend the rest of the morning here, the Oan Carlson seemed to come out of a trance. He swung around to trail Ro up Once Ro stopped to look down into the valley. But Na and the others "You would have liked a more tender goodbye with Charlotte," Ro said to Carlson straightened. He weighed Ro's words before answering. Finally I'm sure he'll see reason when we tell him. It's foolish to be enemies." "Why don't you take her for your wife here on Mars? That would end the trouble completely." Carlson seemed surprised. "It wouldn't be legal. Who would perform the ceremony?" Ro seemed puzzled, then he laughed. "Last night I thought that we on Mars are backward. Now I'm not so sure. When we find our mates here, we take her. There is no one to on Mars your kiss and a promise is probably as binding as any ceremony." Ro didn't speak. He didn't concentrate and transmit his thoughts, but kept them to himself. The pictures he'd received from Carlson

<question>:
Why did Ro change his mind about the people on Mars being backwards?

<options>:
A Because he realized that despite human's technological advancements, they have over-complicated marriage.
B Because he realized that while the humans are physically vulnerable without their weapons, the red people have formidable strength in their arms.
C Because he realized that human males suppress public affection when they are intimidated by other males, whereas male Martians don't hide their affection.
D Because he realized that male humans were petty and even brute when it came to rivalry over women, whereas male Martians were much more civilized.

<answer>:

A