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

<passage>:
entrance to their cave and tell of the wondrous places he'd visited. And, most of all, he wanted to see Na, graceful, dark eyed Na, whose fair face had disturbed his slumber so often, appearing in his dreams to call him home. His handsome face broadened into a smile and he quickened his pace to a trot. There was no need for caution now. The dangers on the plain were few. Mile after mile fell behind him. His long, well muscled legs carried him swiftly toward the distant hills. His movements were graceful, easy, as the loping of Shee, the great cat. Then, suddenly, he faltered in his stride. He stopped running and, figure running toward him. And behind that first figure, a second gave chase. For a long moment Ro studied the approaching creatures. Then he gasped in surprise. The pursued was a young woman, a woman he knew. Na! The pursuer was a squat, ugly rat man, one of the vicious Oan who lived in the cliffs. on his prey to notice Ro at first, and when he did, it was too late. 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 cry. He had seen many Oan die because of the strength and accuracy in the red men's arms. With hardly a glance at his fallen foe, Ro ran on to meet the girl. She ran. The chase was long and tiring. I was almost ready to drop when you appeared." "You were alone in the woods!" Ro exclaimed. "Since when do the women "They were strange men indeed white as the foam on water, and clothed Ro groaned aloud as Na finished her tale. His homecoming was a meeting with tragedy, instead of a joyful occasion. "He had no chance to fight," Na answered. "Two of your brothers died with him on that first morning." Ro squared his shoulders and set his jaw. He wiped a hint of tears from Na trailed behind him. Her face was grave with concern. "They are very many," she said. "Then there will be more to kill," answered Ro without turning. to place. There were no fires, for the Oan were more beast than man and feared flame Her dark eyes seemed to sparkle and her hair shone in the twilight. He understood why she had crept into his dreams. The darkness settled quickly. Soon Ro could barely make out the girl's features. It was time for him to leave. Feeling his way cautiously, he moved toward the camp. He could sense the presence of many Oan close by. The hair at the base of his neck prickled. He prayed he wouldn't be seen. An alarm now would spoil his plan. "The rat men have eyes to cut the night." It was a memory of his mother's voice. She had spoken those words when he was a child, to keep him from straying too far. The Oan was only a few feet away now, but his eyes were not cutting the night. Ro could see his large ears, hear his twitching tail. In a moment the beast would stumble over him. 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 spring amongst them and slay them as they slept. He lay flat on his stomach and inched his way ahead. It was slow work, but safer. When a sound reached his ears he drew himself together and feigned sleep. In the dusk he appeared no different than the others. His chest was scratched in a thousand places when he reached the far contacted a soft body. It seemed to shrink from his touch. A tiny gasp reached his ears. "Be still," he thought. He remembered Na's words: ' was as though he was feeling hide that bound her wrists. He fumbled impatiently with the heavy knots. "Don't move when you are free," he warned the girl as he worked. "I must release the others first. When all is ready I will give a signal Once again his mind grew light. The girl's thoughts assured him she would follow his instructions. 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 "She is the one I have chosen for my mate," Ro answered. The white girl was silent. They traveled quite a distance without should have met them minutes ago. Then he gave a glad cry. Squinting ahead he saw an approaching figure. It was—His cry took on a note of alarm. The figure was bent low under the weight of a burden. It was a rat man, and slung across his shoulders was a girl. Ro's body tensed and quivered. A low growl issued from deep in his throat. He charged forward. 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 The rat man's tail lashed out to twist around Ro's neck. With frantic and lay still. Ro dismounted the limp body. His face wore a wildly triumphant expression. It changed as he remembered the girl. He ran to her side. relief. Na turned her head and saw the body of the rat man. She shuddered. "I was coming down the side of the mountain," she said. "I saw him standing at the foot. The shadows were deceiving. I thought it was you. It wasn't until too late that I discovered my mistake." 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 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 Ro awakened with the dawn. He was startled to find that Na had left his The others in the cave awakened. Ro noticed that Charlotte had slept 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 the rat men?" "The Oan are cowards," Ro answered. "They are brave only because they Ro sprang to his feet to tower above the man. His handsome face was twisted in anger. "You're lying," he shouted aloud, forgetting that the white man couldn't understand his words. "You're lying because you are afraid. You refuse to help me avenge my people because you are more of a coward than the Oan." fists clenched. 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 yourself, you can lure the guards away from their post." 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." 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 Then she will reveal herself." Ro looked at Na for a long moment before they parted. He grew very proud of what he saw. There was no fear in her eyes. Her small chin was firm. be trapped. They would die under a hailstorm of rock. "You would have liked a more tender goodbye with Charlotte," Ro said to Carlson as they worked. "Was it fear of Grimm that prevented it?" 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 Ro seemed puzzled, then he laughed. Ro didn't speak. He didn't concentrate and transmit his thoughts,

<question>:
Why did Ro tell the woman not to move?

<options>:
A She was bound with strips of hide
B He didn't want her to alert the captors
C He needed to hurry
D She was afraid of him

<answer>:

B