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

<passage>:
Marco Four's landfall on the moonless Altarian "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 climate. Stryker blinked and yawned as he let himself through the port, his fringe of white hair tousled and his naked paunch sweating. He to throw off the effects of sleep. Gibson was linguist-ethnologist of "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 Stryker and Farrell traded baffled looks. The city had become something of a fixation with Gibson, and his dogged insistence—coupled with an irritating habit of being right—had worn their patience thin. "There never was a city here, Gib," Stryker said. "You dozed off while we were making planetfall, that's all." 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." A barrage of barbed tentacles lashed out of the foam and drove into the stubbornly. "But it's here somewhere, and I'm going to find it. Will either of you be using the scouter today?" Stryker threw up his hands. "I've a mountain of data to collate, and Arthur is off duty after standing watch last night. Help yourself, but you won't find anything." The scouter was a speeding dot on the horizon when Farrell crawled into his sleeping cubicle a short time later, leaving Stryker to mutter over his litter of notes. Sleep did not come to him at once a vague sense of Marco's planetfall one of the pink fishers had fallen from a casting ledge into the water, and spear-shafts. Which meant that the fishers could not swim, else some would surely have gone in after him. And the Marco's crew had explored Arz exhaustively without finding any completed itself with automatic logic, almost rousing Farrell out of his " He fell asleep with the paradox unresolved. Stryker was still humped over his records when Farrell came out of his cubicle and broke a packaged meal from the food locker. The visicom over the control board hummed softly, its screen blank on open channel. 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 and packed his pipe, settling himself comfortably while Stryker mixed a nightcap before turning in. Later he remembered that Stryker dissolved a tablet in his glass, but at the moment it meant nothing. In a matter of minutes the older man's of dull routine logwork had built up a need for physical action that found it not too unnatural until he came to the motivation and the means how could any Earthman rationalize the outlandish compulsions that actuated so alien a race? He went inside again, and the sound of Stryker's muffled snoring fanned his restlessness. He made his decision abruptly, laying aside the magnoscanner for a hand-flash and a pocket-sized audicom unit which he He did not choose a weapon because he saw no need for one. The torch would show him how the natives reached the outcrop, and if he should need help the audicom would summon Stryker. Investigating without Stryker's sanction was, strictly speaking, a breach of Terran Regulations, but— "Damn Terran Regulations," he muttered. "I've got to He worked deeper into the underbrush and found other sleeping couples, A sharp sting burned his shoulder, wasp-like, and a sudden overwhelming lassitude swept him into a darkness deeper than the Arzian night. His last conscious thought was not of his own danger, but of Stryker—asleep and unprotected behind the Marco's open port.... He was standing erect when he woke, his back to the open sea and a Whatever brought me here anesthetized me first , he thought. That sting in my shoulder was like a hypo needle. more seconds passed before he gained control of himself, sweating with the effort. He had to get help. If he could switch on the audicom at his belt and call Stryker.... He bent every ounce of his will toward raising his right hand, and failed. 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 Marco Four resting between thorn forest and this time the arm tensed a little, enough to send hope flaring through him. If he could put pressure enough against the stud.... The tiny click of its engaging sent him faint with relief. "Stryker!" he yelled. "Lee, roll out— Stryker !" The audicom hummed gently, without answer. He gathered himself for another shout, and recalled with a chill of horror the tablet Stryker had mixed into his nightcap the night before. Worn out by his work, Stryker had made certain that he would not be easily disturbed. its reflected glare he caught a flicker of movement, a restless suggestion of flapping wings. He tried again. "Stryker, help me! I'm on the islet!" The audicom crackled. The voice that answered was not Stryker's, but Gibson's. water below, and felt his shaky laugh of relief stick in his throat. Two of the octopods were swimming strongly for shore, holding the rigid Arzian native carefully above water between them. Marco ." Farrell forced himself to relax, more relieved than alarmed by the painful pricking of returning sensation. "I might have known it, damn In the Marco Four , Gibson routed Stryker out of his cubicle and mixed drinks around, leaving Farrell comfortably relaxed in the padded control chair. The paralysis was still wearing off slowly, easing Farrell's fear of being permanently disabled. Stryker stared. "A marine city? What use would sea-creatures have for buildings?" "Behold a familiar pattern shaping up," Stryker said. He laughed the octopods get curious enough about us to make trouble. Do you feel up to the acceleration, Arthur?" Farrell and Stryker looked at each other, grinning. Farrell said: "You don't think I want to stick here and be used for bait again, do you?" He and Stryker were still grinning over it when Gibson, unamused, blasted the Marco Four

<question>:
What was the narrative purpose of having Stryker take the sleeping pill?

<options>:
A Farrell regularly wakes him by walking around on the ship, and Stryker wanted a good night of sleep.
B Farrell would've tried to ask him questions about the fishermen in the morning had Stryker been awake.
C Taking the pill prevented Stryker from helping Farrell.
D Taking the pill prevented Stryker from helping Marco.

<answer>:

C