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

<passage>:
by CARL JACOBI Grannie Annie, that waspish science-fiction writer, was in a jam again. What with red-spot Grannie became twins every now and then. time, and now as the immense disc of Jupiter flamed across the sky, entered the outer limits of the Baldric. Grannie Annie strode in the As we reached the first of those trees, Grannie came to a halt. on Jupiter's Eighth Moon, and the country was still strange to us. When Annabella C. Flowers, that renowned writer of science fiction, visiphoned me at Crater City, Mars, to meet her here, I had thought she was crazy. But Miss Flowers, known to her friends as Grannie Annie, had always been mildly crazy. If you haven't read her books, you've however, they have one redeeming feature—authenticity of background. Grannie Annie was the original research digger-upper, and when she laid the setting of a yarn on a star of the sixth magnitude, only a transportation-velocity of less than light could prevent her from visiting her "stage" in person. on Jupiter's Eighth Moon, I knew she had another novel in the state of embryo. to do the illustrations for Grannie's new book. Then it was found that this ore, Acoustix, revitalized their sounding apparatus, and the rush was on." "What do you mean?" "What sort of trouble?" Grannie Annie had demanded. And when Antlers And then all at once Grannie stopped again, this time at the top of a awe. The duplicate of myself was talking to the duplicate of Grannie they suddenly faded like a negative exposed to light and disappeared. "What do you make of it?" I said in a hushed voice. Grannie shook her head. "Might be a form of mass hypnosis superinduced by some chemical radiations," she replied. "Whatever it is, we'd better watch our step. There's no telling what might lie ahead." heavens in a single direction, I called Grannie's attention to it. Grannie was shaking his hand vigorously and mumbling introductions. Grannie's eyes glittered. "Trouble with the mine laborers?" she excellent living conditions with a vacation on Callisto every year. Up until a short time ago most of them were in excellent health and spirits. Then the Red Spot Fever got them." "Red Spot Fever?" Grannie looked at him curiously. Jimmy Baker nodded. "The first symptoms are a tendency to garrulousness on the part of the patient. Then they disappear." notebook out, sketching the room's interior. Grannie Annie remained the bottle of Martian whiskey there. "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 men away until the plague has died down?" Grannie Annie walked across to it and began to study its markings. Grannie nodded. "I think you and I and Xartal had better take a run up of the building. Grannie seized a light weight carry-case and began foreboding. Had I been a fool to let Grannie go? I thought of her, an He flicked a stud, and the entire wall above the panel underwent a slow change of colors. Those colors whirled kaleidescopically, then coalesced into a three-dimensional scene. were Jimmy Baker, Grannie, and Xartal. It was as if I were standing "Sure." The operator turned another dial, and Grannie's falsetto voice Miss Flowers there?" "Miss Flowers left with Mr. Baker for Shaft Four," I said. "There's trouble up there. Red spot fever." "A little. But up until yesterday the fever's been confined to the other side of the Baldric. We had one partial case, but my chemists gave the chap an antitoxin that seems to have worked. Come to think of top of them was stretched a translucent web. Jimmy and Grannie got out Jimmy Baker stood next to Grannie, staring up at this incredible mirage. Grannie let out a whoop. "I've got it!" she said. "Those things we see up there are nothing more than mental images. They're Xartal's drawings!" 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 powerful photographic impression of the object. That impression is then transmitted simultaneously in telepathic wavelengths to common The Larynx manager nodded slowly. "I see," he said. "But why don't the 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. of Grannie Annie was bowing to the duplicate of Jimmy Baker, and the "Sorry," the operator said. "I've used too much power already. Have to "That explains something at any rate," the old prospector said. "But how about that Red spot fever?" On Jimmy Baker's desk was a large file marked: FEVER VICTIMS. I opened Reading them over, I was struck by one detail. Each patient had received the first symptoms, not while working in the mines, but while sleeping or lounging in the barracks. part of the button appeared to be a powerful lens of some kind, and as I seized it and pulled it loose, I felt the hum of tiny clock work. All at once I had it! Red spot fever. Heat fever from the infra-red rays of Jupiter's great spot. Someone had constructed this lens to concentrate and amplify the power of those rays. The internal clockwork served a double purpose. It opened a shutter, and it rotated the lens slowly so that it played for a time on each of the sleeping men. I slid the metal button in my pocket and left the barracks at a run. "Turn it on!" was Xartal, the Martian. Grannie Annie was there, but seated at the Ezra Karn jabbed my elbow. "Grannie's coming back. I thought she'd be It was Grannie. As the car drew up alongside I saw her sitting in her "We left the others at the mine. Miss Flowers is going back with me to my offices to help me improve the formula for that new antitoxin." "Ezra!" I yelled, swinging the car. "That wasn't Grannie! the flagpole trees. I had to catch that car I told myself. Grannie Annie's very life might be at stake, not to mention the lives of Grannie Annie. She had a tablet in her hands, and she was writing. "Grannie!" I yelled. "What're you doing here? Where's Mr. Baker?" "Getting back Jimmy's mine laborers," she said, a twinkle in her eyes. bluish radiance spewed from its open end. Playing it back and forth upon the marching men were Jimmy Baker and Xartal, the Martian. "Ultra violet," Grannie Annie explained. "The opposite end of the vibratory scale and the only thing that will combat the infra-red rays that cause red spot fever. Those men won't stop walking until they've reached Shaft Four." Grannie Annie told her story during the long ride back to Shaft Four. For he knew that just as Jupiter's great spot was responsible for a climate and atmosphere suitable for an Earthman on this Eighth Moon, so also was that spot a deadly power in itself, capable when its rays were concentrated of causing a fatal sickness. Then suddenly becoming fearful of Grannie's prying, Antlers Park strove to head her off before she reached Shaft Four. He did head her off and managed to lure her and Baker and Xartal into the Shaft barracks where they would be exposed to the rays from the lens button. But Grannie only pretended to contract the plague.

<question>:
How did Grannie Annie save the workers?

<options>:
A She found the location they all went to and helped them navigate back.
B She removed the lens from the barracks that was making them sick.
C She pretended to contract the fever and fooled Antler Park.
D She discovered that ultraviolet could reverse the effects on them and used it to cure them.

<answer>:

D