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 A. L. HALEY There's a place for every man and a man for every place, but on robot-harried Mars the situation was just a little different. [Transcriber's Note: This etext was produced from Harper Breen sank down gingerly into the new Relaxo-Lounge. He placed Harper tried to let go of everything. He gave in to the chair. And For all of five minutes Harper stood it. Then with a frenzied lunge Harper snorted. His large nose developed the sound magnificently. "Hey, Harp, old man!" His brother-in-law, turning the pages of the new colorama magazine, INTERPLANETARY, had paused at a double-spread. "Didn't you have a finger in those Martian equatorial wells they sunk twenty years ago?" Harper's hands twitched violently. "Don't mention that fiasco!" he rasped. "That deal nearly cost me my shirt! Water, hell! Those wells were the complete antithesis of Harper's picked-crow physique and that those have proved to be the most astoundingly curative springs ever discovered anywhere? Don't you know that a syndicate has built the largest extra-terrestial hotel of the solar system there and that structure of bottle-green glass resting jewel-like on the rufous rock of Mars. The main portion of the building consisted of a circular skyscraper with a glass-domed roof. Between its star-shaped annexes, other domes covered landscaped gardens and noxious pools which in the Harp," he advised. "You'd get a good rest on the way out. This gas they use in the rockets nowadays is as good as a rest-cure it sort of you can finish the cure at the hotel while looking it over. And not only that." Confidentially he leaned toward his insignificant looking brother-in-law. "The chemists over at Dade McCann have just isolated an enzyme from one species of Martian fungus that breaks down crude oil into its components without the need for chemical processing. There's a fortune waiting for the man who corners that fungus market and learns to process the stuff!" Raising the magazine, he began reading the advertisement. And that was when he saw the line about the robots. "—the only hotel staffed entirely with robot servants—" "Robots!" he shrilled. "You mean they've developed the things to that point? Why hasn't somebody told me? I'll have Jackson's hide! I'll "You're right, Bella," agreed Harper incisively. "I'll go and find out The trip out did Harper a world of good. Under the influence of the themselves into deceleration hammocks for the landing. And then Harper Harper was enthralled. He'd staff his offices with them. Hang the robot. Harper watched him shrinking and turning pale lavender in the the hotel is staffed entirely with robots. They're much more expensive, really, than human employees, but so much more efficient, you know. Admit it, they give excellent service, don't they, now?" Toothily he Harper one of the leading business executives of the earth. Harper's pallid smile he pressed a button and consigned Harper to the care of a windows set in the green glass wall framed startling rubicund views of the Martian hinterland where, Harper affectionately thought, fungi were busy producing enzymes that were going to be worth millions for him and his associates. There remained only the small detail of discovering how to extract them economically and to process them on this more than arid and almost airless planet. Details for his bright young laboratory men mere details.... Leaving his luggage to be unpacked by the robot attendant, he went up to the domed roof restaurant. Lunching boldly on broiled halibut with consomme, salad and a bland custard, he stared out at the dark blue sky of Mars, with Deimos hanging in the east in three-quarter phase while Phobos raced up from the west like a meteor behind schedule. Harper opened his eyes. Two robots were bending over him. He saw that Harper's tongue finally functioned. "What's all this?" he demanded. "Tundra?" A faint spark of alertness lightened Harper's dull rage. "You mean you work out here on the tundra?" Enzymes. There's good money in it, but man, what a job! No air worth mentionin'. Temperature always freezin' or below. Pressure suits. Huts. Factory. Processed food. Nothin' else. Just nothin'. That's where they could use some robots. It sure ain't no job for a real live man. And in fact, there ain't many men left there. If old man Hagerty only knew it, ruthless career Harper was up against creatures that he could neither The robots not only ignored Harper. They paid no attention at all to Stolidly they picked Harper up, plunked him into the chair, strapped There was something nagging at Harper's mind. Something he should do. mud-baths and held him there until he was well-done to the bone, he Jake, looking over Harper's skimpy frame, grunted doubtfully. "Maybe Harper looked at his watch. "Time to go. Relax, old man. The robots worry about me. I'll anchor your duds all right." Harper had guessed right. Gleefully from the doorway of his new room twelves. But Harper was a determined man. He didn't even flinch from Only the robots were immune to Harper Breen's progress across the huge in a moss-gray lake, and now he strode manfully toward it, ignoring the oversize trousers slapping around his stocking feet. Only the robots shared his self control. "Call them off!" snarled Harper. "Call them off or I'll ruin your "That's better!" Harper straightened up and meticulously smoothed the "This—this way, sir." With shrinking steps the clerk led Harper across Brushing aside the startled secretary in the outer cubicle, Harper Harper S. Breen! Why, I'll sue you until you'll be lucky if you have a robots, but they haven't yet. Only we had to find it out the hard way. We—" he grimaced disgustedly—"had to pioneer in the use of robots. And it cost us so much that we can't afford to reconvert to human help. Listening, an amazing calm settled on Harper. Thoughtfully now he Meticulously Harper clipped and lit his cigar. "It seems to me that Placidly Harper puffed a smoke ring. "Of course, you'd have to take Harper gazed out at the stunned audience. This was more like the for the second step of his private Operation Robot. Back on Earth it was a warm, misty spring day—the kind of day unknown to the planet Mars. Bella and Scribney, superb in new spring outfits, waited restlessly while the rocket cooled and the passengers recovered from deceleration. And indeed, Harper was stepping briskly downward, looking spry and fit again!" Harper smirked. "Yep, I turned a neat little deal. I bought out Hagerty's Enzymes and staffed the plant with the hotel's robots. Got both of 'em dirt cheap. Both concerns going bankrupt because they didn't have sense enough to swap their workers. Feel I owe you a bit for that tip about enzymes, Scrib, so I made out a block of stock to "All right?" Scribney gulped. Why, the dried-up little turnip was human after all. "All right! Yes, sir! But aren't you going to use some of those robots for office help? Aren't they efficient and all that?"

<question>:
What was Harper's most likely work with the equatorial wells before they sank?

<options>:
A Treating Martian liquids for commercial use.
B Bolstering the Martian tourist economy.
C Converting the wells into curative springs.
D Sourcing water on Mars.

<answer>:

D