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

<passage>:
He was a man of the world now, weary of exploring and ready to settle down. He was anxious to see his family again, his father and mother and all his brothers and sisters And, most of all, he wanted to see Na, graceful, dark eyed Na, whose For a long moment Ro studied the approaching creatures. Then he gasped round rock that would fit his palm—he stooped, and snatching up the on his prey to notice Ro at first, and when he did, it was too late. the red men's arms. eyes were wet with gladness. Warm tears ran down Ro's arm. Finally Na lifted her beautiful head. She looked timidly at Ro, her Na lowered her eyes. "The men of our tribe snatched up stones, and holding one in their woman with golden hair, and the other, a man of age, with hair like silver frost. 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 "And the white ones, as well. They probably keep them alive to repair will set the white ones free. They will help me to make more weapons. 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. The sun was setting when the two Martians reached the cliffs. Below "You say they came from a place called Earth?" Ro asked Na in wonder. He took a pouch from his waist and shook out a gold arm band. This he clasped on Na's wrist. "All men will know now that you are the mate of Ro," he whispered. And he kissed her, as was the custom of his tribe when a man took a wife. Without another word he disappeared over the edge of the cliff. They had already made plans for their next meeting. There was no need for a prolonged farewell. They would be together soon—on the far side of the cliff—if all went well. In his left hand and under his armpit Ro carried stones. They were of a 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 seemed so futile, he whispered the words aloud. Then his mind seemed to grow light, as though someone was sharing the Once again his mind grew light. The girl's thoughts assured him she would follow his instructions. Time passed quickly. To Ro, it seemed that his fingers were all thumbs. golden-haired girl was free. 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. They rose quietly and trailed him into the woods. The girl whispered 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 told them. "After a short while, we will meet Na." "Who is Na?" asked the girl. "She is the one I have chosen for my mate," Ro answered. The white girl was silent. They traveled quite a distance without communicating. Each was busy with his own thoughts. traveled far along the foot of the cliff. According to the plan Na should have met them minutes ago. Then he gave a glad cry. Squinting ahead he saw an approaching figure. 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. fists into his soft stomach. Suddenly shifting his attack, Ro wrapped and tightened. 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. Ro gathered the girl in his arms. He spoke softly to her to help her When she had recovered from her shock, the small group traveled on. Ro Ro smiled. "We will speak of that when it is dawn again," he said with his 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 study." Ro introduced himself and Na. What year is it?" "You have seen what it is like here," Ro answered. "As for 'year,' I don't understand." "A year is a measure of time," the old man explained. "When we left Earth it was the year twenty-two hundred." simple to transmit or receive thoughts from anyone. A mere matter of concentration. We—who speak different tongues—understand each other because of action we have in mind as we speak. We want the other to would like to learn more, but we must sleep now. Tomorrow will be a very busy day." Ro slipped his arm about Na's shoulder and drew her closer. With their Ro awakened with the dawn. He was startled to find that Na had left his a short distance away. Her arms were loaded with Manno, the fruit of Mars, and clusters of wild berries and grapes. "You will make no mate at all," Ro said sternly, "and there will be no 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. The old man also rose. He placed a restraining hand on Ro's arm. I have thought about it all night." Ro turned quickly. he turned back to the others, his attention was centered on Na. "Perhaps the attraction you seem to hold for the Oan can be put to He repeated his plan to the others. "But they'll kill her," gasped Charlotte. when they can." "Then she'll be captured," the professor said. "It's much too risky." Ro laughed. "Do you think I will let her go alone? I will be close by. Na can lead can kill each other. But not until then." Grimm brushed himself off as he got to his feet "Okay," he sneered. "I'll go with the red man. But when we meet again, it will be a different story." "I'll go with you," he said. "Grimm can go with Charlotte and the 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 Then she will reveal herself." 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 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 he said, "I didn't want to make trouble. It was a bad time, and senseless, besides. Charlotte and I are planning to be married when we return to America. It's not as though Grimm was still in the running. 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 speak of 'legal' or 'ceremony.' After all, it's a personal matter. Who can tell us whether it is 'legal' or not? What better ceremony than a kiss and a promise?" He bent back to his work chuckling. "I could argue the point," Carlson laughed. "I could tell you about a place called Hollywood. Marriage and divorce is bad enough there. Under your system, it would really be a mess. But I won't say anything. Here 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>:
What does the gold band that Ro put on Na's wrist mean for them?

<options>:
A They are engaged.
B They are combat mates.
C They are married.
D They are dating.

<answer>:

C