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

<passage>:
was a question as to which was which. The third night of the Marco Four's landfall on the moonless Altarian planet was a repetition of the two before it, a nine-hour intermission stand watch—was sitting at an open-side port with a magnoscanner ready but in spite of his vigilance he had not exposed a film when the inevitable pre-dawn rainbow began to shimmer over the eastern ocean. Sunrise brought him alert with a jerk, frowning at sight of two pinkish, bipedal Arzian fishermen posted on the tiny coral islet a quarter-mile offshore, their blank triangular faces turned stolidly toward the beach. "They're at it again," Farrell called, and dropped to the mossy turf outside. "Roll out on the double! I'm going to magnofilm this!" Stryker and Gibson came out of their sleeping cubicles reluctantly, belting on the loose shorts which all three wore in the balmy Arzian heavy brows that shaded a square, humorless face. "Any sign of the squids yet?" he asked. "They won't show up until the dragons come," Farrell said. He adjusted the light filter of the magnoscanner and scowled at Stryker. "Lee, I wish you'd let me break up the show this time with a dis-beam. This butchery gets on my nerves." Stryker shielded his eyes with his hands against the glare of sun on water. "You know I can't do that, Arthur. These Arzians may turn out to be Fifth Order beings or higher, and under Terran Regulations our gathering, nets and fishing spears in hand, at the edge of the sheltering bramble forest. "What stumps me is their motivation," he said. "Why do the fools go out to that islet every night, when they must know damned well what will happen next morning?" irritating habit of being right—had worn their patience thin. we were making planetfall, that's all." Gibson stiffened resentfully, but Farrell's voice cut his protest short. "Get set! Here they come!" Out of the morning rainbow dropped a swarm of winged lizards, twenty feet in length and a glistening chlorophyll green in the early light. They stooped like hawks upon the islet offshore, burying the two Arzian fishers instantly under their snapping, threshing bodies. Then around the outcrop the sea boiled whitely, churned to foam by a sudden uprushing of black, octopoid shapes. "The squids," Stryker grunted. "Right on schedule. Two seconds too late, as usual, to stop the slaughter." melee of winged lizards. The lizards took the air at once, leaving behind three of their number who disappeared under the surface like harpooned seals. No trace remained of the two Arzian natives. magnoscanner. "Do any of those beauties look like city-builders, Gib?" Chattering pink natives straggled past from the shelter of the thorn forest, ignoring the Earthmen, and lined the casting ledges along the Arthur is off duty after standing watch last night. Help yourself, but you won't find anything." something overlooked prodded irritatingly at the back of his consciousness, but it was not until drowsiness had finally overtaken him that the discrepancy assumed definite form. He recalled then that on the first day of the Marco's completed itself with automatic logic, almost rousing Farrell out of his doze. "I'll be damned," he muttered. "No boats, and they don't swim. Then how the devil do they get out to that islet? " He fell asleep with the paradox unresolved. Stryker snorted. "He's scouring the daylight side now," Stryker said. "Arthur, I'm going to ground Gib tomorrow, much as I dislike giving him a direct order. He's got that phantom city on the brain, and he lacks the imagination to bullheaded habit of being right. I hope he finds it soon, if it's here. I'll probably be standing his watch until he's satisfied." Stryker looked relieved. "Would you mind taking it tonight? I'm completely bushed after today's logging." Farrell waved a hand and took up his magnoscanner. It was dark outside already, the close, soft night of a moonless tropical world whose moist atmosphere absorbed even starlight. He dragged a chair to the open port the islet each morning, and the coincidence made him sit up suddenly, startled. Why two? Why not three or four, or only one? He stepped out through the open lock and paced restlessly up and down on "Damn Terran Regulations," he muttered. "I've got to know ." mossy ground, sleeping soundly, their triangular faces wholly blank and unrevealing. He worked deeper into the underbrush and found other sleeping couples, but nothing else. There were no humming insects, no twittering night-birds or scurrying rodents. He had worked his way close to the center of the island without further discovery and was on the point of from behind. and unprotected behind the Marco's He was standing erect when he woke, his back to the open sea and a prismatic glimmer of early-dawn rainbow shining on the water before him. For a moment he was totally disoriented then from the corner of an eye He was on the coral outcropping offshore, and except for the involuntary muscles of balance and respiration his body was paralyzed. The first red glow of sunrise blurred the reflected rainbow at his feet, but for some seconds his shuttling mind was too busy to consider the danger of predicament. Whatever brought me here anesthetized me first , Panic seized him again when he remembered the green flying-lizards more seconds passed before he gained control of himself, sweating with the His arm was like a limb of lead, its inertia too great to budge. He relaxed the effort with a groan, sweating again when he saw a fiery half-disk of sun on the water, edges blurred and distorted by tiny surface ripples. On shore he could see the Worn out by his work, Stryker had made certain that he would not be easily disturbed. The flattened sun-disk on the water brightened and grew rounder. Above its reflected glare he caught a flicker of movement, a restless suggestion of flapping wings. here fast, Gib! The flying-lizards—" He broke off, seeing for the first time the octopods that ringed the unmistakable flapping of wings behind and above him then, and thought now I'm one of the cast . The scouter roared in from the west across the thorn forest, flashing so Gibson met the lizard swarm head on. "None," Gibson said. "I think the city must have been built ages ago—by men or by a manlike race, judging from the architecture—and was submerged later by a sinking of land masses that killed off the original took over then, and from all appearances they've developed a culture of their own." "I don't see it," Stryker complained, shaking his head. "The pink fishers—" "Are cattle, or less," Gibson finished. "The octopods are the dominant race, and they're so far above Fifth Order that we're completely out of bounds here. Under Terran Regulations we can't colonize Arz. It would be armed invasion." "Because the octopods own the islands too, and keep them policed," world, Arthur, don't you see? And like most civilized peoples, they're sportsmen. The flying-lizards are the game they hunt, and they raise the pink fishers for—" Farrell swore in astonishment. "Then those poor devils are put out there the octopods get curious enough about us to make trouble. Do you feel up

<question>:
How do the characters know when the winged lizards will appear?

<options>:
A The winged lizards are unpredictable
B They appear at daybreak every morning
C They make screeching sounds as they fly
D They only appear when the sun is setting

<answer>:

B