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

<passage>:
to gyp a space-lane sucker. Or so they thought! Angus Johnson knew differently. He charged them five buckos for a glass of water—and got it! In their hectic voyages from planet to planet, the pair of panacea remaining pair. The bartender, a big man resembling the plumpish Harvey in build, was leaning negligently on the counter, ordering this impossible being to fill the partly-emptied bottles, squeeze fruit things to know there are always more." He led the way inside. Through thirst-cracked lips he rasped: "Water—quick!" Without a word, the bartender reached under the counter, brought out "We did. He came near starving and moved on to Titan. Ships don't land here unless they're in trouble." "Then where's the water lead-in? We'll fill up and push off." "Mayor takes care of that," replied the saloon owner. "If you gents're Harvey grinned puzzledly. "We didn't take any whiskey." "Might as well. Water's five buckos a glass. Liquor's free with every chaser." Harvey's eyes bulged. Joe gulped. "That—that's robbery!" the lanky man Harvey nudged him warningly. "Easy, my boy, easy." He turned to the bartender apologetically. "Don't mind my friend. His adrenal glands are The round face of the barkeeper had assumed an aggrieved expression. "Folks are always thinkin' the other feller's out to do 'em," he said, shaking his head. "Lemme explain about the water here. It's bitter as some kinds of sin before it's purified. Have to bring it in with buckets and make it sweet. That takes time and labor. Waddya think—I was chargin' feller critters for water just out of devilment? I charge because I gotta." thirst." The saloon man removed his dirty apron and came around the bar. "Let's say ten buckos a liter," the mayor said. "On account of the quantity, I'm able to quote a bargain price. Shucks, boys, it hurts me more to charge for water than it does for you to pay. I just got to, that's all." wetted his lips expectantly. Harvey bravely counted off the bills. He asked: "But what are we to do about replenishing our battery fluid? Ten buckos a liter would be preposterous. We simply can't afford it." Johnson's response almost floored them. "Who said anything about charging you for battery water? You can have all you want for nothing. It's just the purified stuff that comes so high." After giving them directions that would take them to the free-water picked up buckets that hung on the tank. "Johnson, as I saw instantly, is the victim of a difficult environment, and must charge accordingly." "Just the same," Joe griped, "paying for water isn't something you can get used to in ten minutes." In the fragile forest, they soon came across a stream that sprang from the igneous soil and splashed into the small pond whose contents, according to the mayor, was theirs for the asking. They filled their "What's this doing here?" Harvey asked, puzzled. "I thought Johnson had to transport water in pails." "Wonder where it leads to," Joe said uneasily. "It leads "I am growing suspicious," he said in a rigidly controlled voice. But Joe was already on his knees, scooping up a handful of water and tasting it. "Sweet!" he snarled. They rushed back to the first pool, where Joe again tasted a sample. His mouth went wry. "Bitter! He uses only one pool, the sweet one! The only thing that needs purifying around here is that blasted mayor's conscience." Him and me are the whole Earthman population of Johnson City." Johnson's eight-foot son, topped by a massive roof of sun-bleached hair "Bring him in here!" Johnson cried. "I mean, get him away! He's coming ?" demanded Johnson. "I come down with it every year, and I ain't hankering to have it in an off-season. Get him out of here!" "In good time. He can't be moved immediately." "Then he'll be here for months!" Instead of replying, Harvey hurried outside to the ungainly second-hand rocket ship in the center of the shabby spaceport. He returned within a few minutes, carrying a bottle. When Joe tried to pull away, Harvey was inexorable. He made his partner drink until most of the liquid was gone. Then he stepped back and waited for the inevitable result. the man gradually won. "There ain't no words for that taste," he gulped when it was safe to his murderous silence and cried: "What kind of a dirty trick was that, giving me poison instead of that snake oil?" mind you. Was I to mix the extract with the water for which we had been swindled to the tune of ten buckos a liter? Where would our profit have been, then? No I had to use the bitter free water, of course." "But why use it on me?" Joe demanded furiously. Harvey looked reprovingly at his gangling partner. "Did Johnson ask to him, reverently uncorked a bottle and sampled it. It must have been at least as good as the first he gagged. "That's the stuff, all right," he said, swallowing hard. He counted out the money into Harvey's hand, at a moderate rate that precariously balanced between his pleasure at getting the fever remedy and his pain Harvey and Joe looked at each other. They hadn't been thinking about food at all, but suddenly they realized that they were hungry. "It's only water we were short of," Harvey said apprehensively. "We've got rations back at the ship." " Johnson immediately fell into the role of "mine host." chance of company. Genius, the six-armed native, appeared from the dingy kitchen with two menus in one hand, two glasses of water in another, plus napkins, complained Harvey. "I wish Johnson would stay either swindler or honest Johnson didn't answer. Neither did Genius "Either one. It don't make no difference. Genius is too valuable to sell." "Oh, come now, Mr. Johnson. Don't tell me no amount of money would tempt you!" Johnson. "I should imagine you will be rather lonely, with only your Joe's face grew as glum as Johnson's had been. "Aw, Harv," he protested, "do we have to sell it? And right when I thought we were getting the key!" "We must not be selfish, my boy," Harvey said nobly. "We have had our chance now we must relinquish Fate to the hands of a man who might have more success than we. Go, Joseph. Bring it here." On a larger and heavier world than Planetoid 42, Johnson's curiosity would probably have had weight and mass. He was bursting with questions, but he was obviously afraid they would cost him money. For his part, Harvey allowed that curiosity to grow like a Venusian amoeba "Do not jump to hasty conclusions," Harvey cautioned. "Another word, and I shall refuse you the greatest opportunity any man has ever had, with the sole exceptions of Joseph, myself and the unfortunate inventor He has spurned our generosity. We have now the chance to continue our study, which I am positive will soon reward us with the key to an enormous fortune." saying I'll buy, but what is it I'm turning down?" "Why, I don't know," Johnson said in confusion. failed. But that was understandable a sensitive soul like his could stand only so much. And the combination of ridicule and failure to solve the mystery caused him to take his own life."

<question>:
Why does Johnson stay on the asteroid, even though few people come by?

<options>:
A Here he's able to meet traders like Harvey and Joe and barter with them.
B He's able to run business even with few customers.
C Here he's able to take advantage of travelers who are lost or in need of supplies.
D He doesn't want to give up the spring of water.

<answer>:

C