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

<passage>:
DOUBLE TROUBLE Grannie Annie, that waspish science-fiction writer, was in a jam again. What with red-spot fever, talking cockatoos and flagpole trees, I was running in circles—especially since Grannie became twins every now and then. Extensive research did not uncover any evidence that Interstellar Voice three days ago, Earth time, and now as the immense disc of Jupiter flamed across the sky, He could be excused this time, however, for this was only our third day , and other works of science fiction. Blood-and-thunder as these books are, however, they have one redeeming feature—authenticity of background. "What do you mean?" "There are two companies here," he continued, " . Chap by the name of Jimmy Baker runs that. However, the point is, between the properties of these two companies stretches a band or belt which has become known as the Baldric. "There are two principal forms of life in the Baldric flagpole trees and a species of ornithoid resembling cockatoos. So far no one has crossed the Baldric without trouble." "What sort of trouble?" Grannie Annie had demanded. And when Antlers Silver in plumage, it resembled a parrot with a crest and yet it didn't. In some strange way the thing was a hideous caricature. "Look what I found," I yelled. "What I found," said the cockatoo in a very human voice. "Thunder, it talks," I said amazed. "Talks," repeated the bird, blinking its eyes. The cockatoo repeated my last statement again, then rose on its short legs, flapped its wings once and soared off into the sky. Xartal, the Martian illustrator, already had a notebook in his hands and was sketching a likeness of the creature. cockatoos and more flagpole trees. Above us, the great disc of Jupiter began to descend toward the horizon. party of four persons. In the lead was a little old lady in a black dress. Behind her strode a grizzled Earth man in a flop-brimmed hat, another Earth man, and a Martian. Detail for detail they were a duplicate of ourselves! "A mirage!" said Ezra Karn. awe. The duplicate of myself was talking to the duplicate of Grannie the sand seemed to grow more and more powdery. For some time I had fixed my gaze on a dot in the sky which I supposed to be a high-flying cockatoo. As that dot continued to move across the heavens in a single direction, I called Grannie's attention to it. "It's a kite," she nodded. "There should be a car attached to it "This is Jimmy Baker," she said. "He manages questioned. spirits. Then the Red Spot Fever got them." Jimmy Baker nodded. "The first symptoms are a tendency to garrulousness on the part of the patient. Then they disappear." them. We tried following them, of course, but it was no go. As soon as they realize they're being followed, they stop. But the moment our eyes "But surely you must have some idea of where they go," Grannie said. Baker lit a cigarette. "There's all kinds of rumors," he replied, "but none of them will hold water. By the way, there's a cockatoo eyrie ahead of us." I followed his gaze and saw a curious structure suspended between a rude circle of flagpole trees. A strange web-like formation of translucent gauzy material, it was. Fully two hundred cockatoos were perched upon it. They watched us with their mild eyes as we passed, but they didn't move. "There must be ways of stopping this," she said. "Have you called in any physicians? Why don't you call an enforced vacation and send the I may have to do that, but when I do, it means quits. Our company is to produce during a period of thirty days or more, and you lose all threw off the switch. happened to Annabella C. Flowers, I would never forgive myself and coalesced into a three-dimensional scene. were Jimmy Baker, Grannie, and Xartal. It was as if I were standing directly behind them. "It's Mr. Baker's own invention," the operator said. "An improvement on the visiphone." "Do you mean to say you can follow the movements of that car and its "Miss Flowers left with Mr. Baker for Shaft Four," I said. "There's trouble up there. Red spot fever." it, I might drive over to Shaft Four and give Jimmy Baker the formula. trouble, I shouldn't either." Then once more I was directly behind my friends, listening in on their conversation. The view through the windscreen showed an irregular array of flagpole trees, with the sky dotted by high-flying cockatoos. "There's an eyrie over there," Jimmy Baker was saying. "We might as well camp beside it." the proper shading and then go on to the next. In swift rotation likenesses of Ezra Karn, of myself, of Jimmy Baker, and of Antlers Park took form. Ezra spoke over my shoulder. "He's doing scenes for Grannie's new Look at that damned nosy bird! " A silver cockatoo had alighted on the kite car and was surveying curiously Xartal's work. As each drawing was completed, the bird scanned it with rapt attention. Abruptly it flew to the top of the eyrie, where it seemed to be having a consultation with its bird companions. And then abruptly it happened. The cockatoos took off in mass flight. A group of Earth people suddenly materialized on the eyrie, talking and moving about as if it were the most natural thing in the world. With a shock I saw the likeness of myself the image of Jimmy Baker. The "Those things we see up there are nothing more than mental images. They're Xartal's drawings!" "Don't you see," the lady continued. "Everything that Xartal put on paper has been seen by one or more of these cockatoos. The cockatoos are like Earth parrots all right, but not only have they the power of copying speech, they also have the ability to recreate a mental image of what they have seen. In other words their brains form a powerful photographic impression of the object. That impression is then transmitted simultaneously in telepathic wavelengths to common foci. That eyrie might be likened to a cinema screen, receiving brain vibrations from a hundred different sources that blend into the light birds reconstruct images from the actual person. Why use drawings?" "Probably because the drawings are exaggerated in certain details and made a greater impression on their brains," Grannie replied. Up on the eyrie a strange performance was taking place. The duplicate of Grannie Annie was bowing to the duplicate of Jimmy Baker, and the it and found it contained the case histories of those men who had been attacked by the strange malady. something screwy here." "Ezra!" I yelled, swinging the car. "That wasn't Grannie! That was one of those damned cockatoo images. We've got to catch him." The other car was some distance ahead now. Park looked back and saw us Annie's very life might be at stake, not to mention the lives of sent it coiling across the intervening space. themselves in a long flanking corridor in a northwesterly direction, as that cause red spot fever. Those men won't stop walking until they've Jimmy Baker had struck a new big lode of Acoustix, a lode which if Interstellar Voice . Antlers Park didn't want that. Then suddenly becoming fearful of Grannie's prying, Antlers Park strove He did head her off and managed to lure her and Baker and Xartal into lens button. But Grannie only pretended to contract the plague. Park then attempted to outwit Ezra Karn and me by returning in Jimmy Baker's kite car with a cockatoo image of Grannie.

<question>:
Why does the party run into duplicates of themselves?

<options>:
A It's the Red Fever influencing their perception.
B As Grannie Annie says, it's a form of mass hypnosis.
C They're a mirage, a result of the Baldric.
D They're the cockatoos, copying their appearance.

<answer>:

D