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

<passage>:
Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Every boy should be able to whistle, except, of course, Martians. But this one did! He seemed a very little boy to be carrying so large a butterfly net. He swung it in his chubby right fist as he walked, and at first glance you couldn't be sure if he were carrying it, or it carrying him . He came whistling. All little boys whistle. To little boys, whistling is as natural as breathing. However, there was something peculiar about this particular little boy's whistling. Or, rather, there were two things peculiar, but each was related to the other. do not—and he most certainly didn't. The second was the tune he whistled—a somehow familiar tune, but one which I should have thought not very appealing to a little boy. "Hi, there," I said when he came near enough. "What's that you're whistling?" He stopped whistling and he stopped walking, both at the same time, as ?" I asked. "From the William Tell Overture," he explained, still looking up at me. He said it deadpan, and his wide brown eyes never once batted. I blinked at him. He didn't blink back. His round little face still held no expression, but if it had, I knew it would have matched the title of the tune he whistled. "You whistle very well," I told him. That pleased him. His eyes lit up and an almost-smile flirted with the corners of his small mouth. He nodded grave agreement. "Been after butterflies, I see. I'll bet you didn't get any. This is the wrong season." The light in his eyes snapped off. "Well, good-by," he said abruptly "Good-by," I said. His whistling and his walking started up again in the same spot where I followed him with my eyes. An unusual little boy. A most precisely little boy. When he was almost out of sight, I took off after him, wondering. mother had taught him the William Tell Overture, had she? That tickling thought made me chuckle as I stood before the ramshackle building. And then, suddenly, I stopped chuckling and began to think, instead, of something quite astonishing: How had it been possible for her to teach, and for him to whistle? "You're Mobile Security, aren't you? Or is that badge you're wearing just something to cover a hole in your shirt?" "Yes, I'm Security, but does it have to mean something?" I asked. "All interested in who you are. It's the little boy who just went in here to somewhere else in the house. Nowhere did I see the little boy. I I smiled reassuringly. "Nothing, lady, nothing. I'm sorry I upset you. I was just being nosy is all, and that's the truth of it. You see, the little boy went by me a while ago and he was whistling. He whistles For a moment, I just blinked stupidly at her, as I had blinked stupidly at the little boy when he told me his mother had taught him how to I finally said: "So that is why he is able to whistle." She didn't answer. Even before I spoke, her eyes had seen the correct coated with honey. "Get the hell out of here, you fool!" immediately puts it to use—on you. I looked up just in time to avoid running into a spread-legged man who was standing motionless directly in the middle of the sand-path in in the sand and was away. I stood there staring at his rapidly disappearing form for a few moments and then looked back once more at the house. A tattered cotton curtain was just swinging to in the dirty, He was a killer named Harry Smythe. I took the picture into the Chief's office and laid it on his desk, waited for him to look down at it and study it for an instant, and then to look back up to me. Which he did. "So?" he said. "Wanted, isn't he?" " He nearly leaped out of his chair. "I didn't know who he was at first," I said. "It wasn't until I looked I spent the remainder of the afternoon trying to get a lead on him and got nowhere. If he was hiding in any of the places I went to, then he lapel directly above my badge, and went through the gates. The huge circle fire was burning and the dance was in progress. Briefly, this can be described as something like the ceremonial dances The dancers were both men and women and they were as naked as Martians can get, but their dance was a thing of grace and loveliness. For an instant—before anyone observed me—I stood motionless and watched the sinuously undulating movements, and I thought, as I have often drawn-back, great, sucking breath. For, somewhere outside, somewhere near that dancing circle, in perfect time with the lively beat of the drums, somebody was whistling. It was a clear, clean sound, a merry, bright, happy sound, as sharp He only looked at me for another dull instant and then his eyes slowly closed and his hands folded together in his lap. Being caught in a lie circle and the dancers within, and, too, I suppose, to her small son who was somewhere in that circle with them, whistling. She leaned against the bole of a belu If that meant anything to her, I couldn't tell. In the flickering light from the fires, subtle changes in expression weren't easily detected. whoever it was, I'll get him. I'll get him! " And then, suddenly, it wasn't. Even though the noise of the dance and the dancers was loud enough to command the attention and the senses. I of speed and savagery combined and those who moved to its frenetic jabberings were not dancers any more, but only frenzied, jerking figurines on the strings of a puppeteer gone mad. I looked down again at the woman. "Your little boy and his butterfly net," I said softly. "In a season when no butterflies can be found. What was that for? Was he part of the plan, too, and the net just the alibi that gave him a passport to wander where he chose? So that he could listen, pick up a little information here, a little there?" that? Next day I followed the little boy. He left the reservation in a cheery frame of mind, his whistle sounding loud and clear on the thin morning air. He didn't go in the direction of town, but the other way—toward the ruins of the ancient Temple City of the Moons. I watched his chubby arm and the swinging of the big butterfly net on the end of that arm. Then I followed along in his sandy tracks. It was desert country, of course. There wasn't any chance of tailing we came to the rag-cliffs, those filigree walls of stone that hide the entrance to the valley of the two moons. Once there, he paused and placed his butterfly net on a rock ledge and then calmly sat down and took off his shoes to dump the sand while he waited for me. He looked up at me. He nodded politely. Then he put on his shoes again and got to his feet. "You've been following me," he said, and his brown eyes stared accusingly into mine. satisfactory?" "Quite, sir." Without another word, he picked up his butterfly net and disappeared along a path that led through a rock crevice. Only then did I allow myself to grin. It was a sad and pitying and affectionate kind of grin. I sat down and did with my shoes as he had done. There wasn't any hurry himself of finding the killer of his daddy. like breast bones from the desiccated carcass of an animal. For a moment I stopped and stared down at the ruins. I didn't see the boy. He was somewhere down there, though, still swinging his butterfly net and, probably, still whistling. I started up once more.

<question>:
Why does the boy likely carry a net?

<options>:
A To try to catch butterflies
B To defend himself
C To help him whistle
D To look like he is catching butterflies

<answer>:

D