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

<passage>:
Sisko Rolf was fighting his greatest Sisko Rolf's stocky body was a blur of motion as he cut the rocket "Trapped us neatly," Rolf said through clenched teeth. "Tolled into can't escape, that's certain. They know these caverns better than.... We'll down some of them, though." "Right!" That was old Garmon Nash, his fellow patrolman aboard the Rolf swung the lax controls over hard as the bursts of fire revealed a of the flyer crumple inward. The cabin seemed to telescope about him. In a slow sort of wonder Rolf felt the scrape of rock against metal, and then the screeching of air through the myriad rents in the cabin's Down plunged the battered ship, downward ever downward. Somehow Rolf momentarily, but the nose of the vertically plunging ship dissolved split open like a rotten squash, and Rolf felt himself that he lay crushed against a rocky wall. Much later Rolf groaned with the pain of bruised muscles and tried to sharp breathlessness that strained at his chest meant cracked ribs. There was light in the narrow pit in which he found himself, light and heat from the yet-glowing debris of the rocket flyer. The outlaws had blasted the crashed ship, his practiced eyes told him, and Garmon Nash must have died in the wreckage. He was alone in the waterless trap of a deep crevice. Rolf laughed. Without a pressure mask on the surface of Mars an flooded into his muscles he set off around the irregular wall of the pit. He found the opening less than ten paces from the starting point, an light reached his eyes Rolf did not know—it had seemed an eternity of "They may have found the sunken seas of Mars," thought Rolf as he moved his feet had betrayed him, and he realized that he had fallen through the other half. Toward this barrier the spinner bore him, and Rolf was it seemed to Rolf that he must be falling free through black dust, and he came to a stop. Deftly Rolf nested the rocks ahead. Rolf's slitted gray eyes narrowed yet more and his hand The voice had spoken in English! Rolf took a step forward eagerly and Rolf found himself staring, open-mouthed, at the sleek-limbed vision "Altha," he scolded, scrubbing at his reddened bald skull with a The girl laughed, a low liquid sound that made Rolf's heart pump She smiled again as Rolf's face slowly reddened. "Do not be ashamed," Rolf threw up the mental block that was the inheritance from his "Sorry," said the tall man as Rolf sprang easily from the ground to "She one of them?" Rolf's voice was low, but he saw Altha's lip twitch. Rolf followed the direction of the other's pale blue eyes. Overhead now lifted above the restless dark waters of a vast sea. Rolf realized with a wrench of sudden fear that they actually hung head downward like "One," repeated Rolf slowly. "You mean there are more?" Rolf felt new strength pump into his tired bruised muscles. Here lay "Mark!" The girl's voice was tense. Rolf felt her arm tug at his sleeve "I will take the glider." Altha was on her feet, her body crouched Rolf watched the column of barbarically clad warriors file out upon the Rolf's eyes slitted. There was something vaguely unhuman about those Rolf raised his expoder, red anger clouding his eyes as he saw these Rolf and Mark Tanner came to their feet. Rolf's expoder rattled briefly like a high-speed sewing machine as he The expoder hammered in Rolf's heavy fist. Tanner smashed an elbow into Rolf's side. "Retreat!" he gasped. "Now where?" Rolf snapped another burst of expoder needles at the furry shattered heart. An unseen furry shape sprang upon Rolf's shoulders Tanner's finger pointed. "Altha!" Rolf saw the graceful wings of the glider riding the thermals back toward the Barrier. "She had warned the "The weasel heads won't follow us here?" asked Rolf. Rolf laughed. "Like the pleasure globes of the wealthy on Earth." "But," Rolf frowned thoughtfully, "what keeps Lomihi from crashing into Rolf caught a glimpse of a sleek rocket flyer diving upon Altha's frail section of the wall swung slowly inward. Rolf sprang to his side. The older man's eyes were hot. He jerked at Rolf's hands and then Rolf pushed up and outward with all the strength of his weary muscles. The glider knifed forward with that first swift impetus, and drove out had taken shelter, noting as he did so that the rocket flyer had landed A man stood on guard just outside the flyer's oval door. Rolf lined up comrades. But if the outlaw saw him Rolf knew that he would be the about. Rolf pressed the firing button Rolf snapped his weapon overhand at the Frog's hairless skull. The momentarily. In that instant Rolf launched himself from the open They went down, Rolf swinging his fist like a hammer. He felt the Frog go limp and he loosed a relieved whistle. Now with a rocket flyer and not too tight, the man could free himself in the course of a few hours. He shrugged his shoulders wearily and started to get up. A green bulge showed around the polished fuselage and Rolf pressed his captured weapon's firing button. A roar of pain came from the wounded And something that felt like a mountain smashed into his back. He was crushed downward, breathless, his eyes glimpsing briefly the soiled This sledge was hammering relentlessly as Rolf sensed his first undisciplined men would have permitted to accumulate. Cautiously his head twisted until he could look forward toward the as he moved his arm. But Rolf had learned that his limbs were not The ship bumped gently as it landed and the thrum of rockets ceased. The cabin shifted with the weight of bodies moving from their seats. Rolf heard voices from a distance and the answering triumphant bawling oily floor flame. He lay unmoving while the thick smoke rolled over him. "Fire!" There was panic in the outlaw's voice. Rolf came to his knees not on the prisoners, and so the impact of Rolf's horizontally The outlaw was game. His fists slammed back at Rolf, and his knees jolted upward toward the patrolman's vulnerable middle. But Rolf smoke, and then the fingers of the outlaw clamped around Rolf's throat The patrolman was weary the wreck in the upper cavern and the long trek afterward through the dark tunnels had sapped his strength, and now he felt victory slipping from his grasp. He felt something soft bump against his legs, legs so far below that he he heard a cry of pain and the blessed air gulped into his raw throat. Rolf swung, all the weight of his stocky body behind the blow, and the himself into the spongy control chair's cushions and sent the ship rocketing skyward. Behind him the thin film of surface oil no longer burned and the conditioning unit was clearing the air. "Everything bongo?" Rolf wanted to know. "Of course," she smiled crookedly. "Glad of that." Rolf felt the warmth of her body so close beside him. A sudden strange restlessness came with the near contact. Altha smiled shyly and winced with pain. "Do you know," she said, "even Rolf grinned up at her. "Need to?" he asked. Then they were over the Barrier and Rolf saw the last of the beaten Rolf snorted. "Shorty," he said disgustedly as they landed, but his arm

<question>:
After realizing his situation after the crash, why did Rolf laugh?

<options>:
A He was facing certain death
B His laughter was caused from the thick air
C He was satisfied with their journey.
D He was happy to be away from Garmon

<answer>:

A