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

<passage>:
Harper Breen sank down gingerly into the new Relaxo-Lounge. He placed For all of five minutes Harper stood it. Then with a frenzied lunge he escaped the embrace of the Relaxo-Lounge and fled to a gloriously stationary sofa. Franz said it would be just the thing for you! Why won't you give it a trial?" causing your trouble. He told you to take a long vacation or you'd Harper snorted. His large nose developed the sound magnificently. "Vacation!" he snorted. "Batting a silly ball around or dragging a hook me to a crack-up. It's the strain of trying to get some sensible, reasonable coöperation from the nincompoops I have to hire! It's the idiocy of the human race that's got me whipped! It's the—" "Hey, Harp, old man!" His brother-in-law, turning the pages of the Harper's hands twitched violently. "Don't mention that fiasco!" he nervous tribulations were beginning to bore him, as well as interfere with the harmony of his home. "You're away behind the times, Harp," he declared. "Don't you know 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 people are flocking to it to get cured of whatever ails 'em? Old man, you missed a bet!" Leaping from the sofa, Harper rudely snatched the magazine from Dutifully Scribney remembered and commented on the change the Martian springs had effected in the Durants. "It's the very thing for you, 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!" Scribney had gauged his victim's mental processes accurately. The calculating. He even forgot to twitch. "Maybe you're right, Scrib," he acknowledged. "Combine a rest-cure with business, eh?" Raising the magazine, he began reading the advertisement. And that was when he saw the line about the robots. "—the only hotel staffed "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 disfranchise him! I'll—" The trip out did Harper a world of good. Under the influence of the soporific gas that permeated the rocket, he really relaxed for the copper-glass, and at the vistas of beautiful domed gardens framed by a dozen arches. But most of all, the robots won his delighted approval. He could see at once that they had been developed to an amazingly high state of perfection. How, he wondered again, had this been done without his knowledge? Was Scrib right? Was he slipping? Gnawing at the doubt, he watched the robots moving efficiently about, pushing patients in expense! There'd be no more of that obnoxious personal friction and proneness to error that was always deviling the most carefully trained office staffs! He'd investigate and find out the exact potentialities of these robots while here, and then go home and introduce them into the field of business. He'd show them whether he was slipping! Briskly he went over to the desk. He was immediately confronted with a sample of that human obstinacy that was slowly driving him mad. Machines, he sighed to himself. But she had turned her glare on Harper. "You could at least be civil implacable stare won his point. Wiping beads of moisture from his forehead, the clerk fumbled for a card, typed it out, and was about to 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.... Leaning back in his cushioned chair, he even more boldly lit a slim cigar—his first in months—and inhaled happily. For once old Scribney had certainly been right, he reflected. Yes sir, Scrib had rung the bell, and he wasn't the man to forget it. With a wonderful sense of well-being he returned to his room and prepared to relax. Harper's tongue finally functioned. "What's all this?" he demanded. Harper scowled. "Oh, haven't I?" he grated. "Robots! Do you know what try it!" He ground his teeth together in futile rage. "And to think I had the insane notion that robots were the last word! Why, I was ready Harper sat up as if he'd been needled. He opened his mouth to speak. wrong with me! Take it away! I'm only here for a rest-cure! Believe me! Take it away!" The robots ignored him. For the first time in his spectacular and ruthless career Harper was up against creatures that he could neither bribe, persuade nor browbeat, inveigle nor ignore. It shattered his ebbing self-confidence. He began waving his hands helplessly. The robots not only ignored Harper. They paid no attention at all to There was something nagging at Harper's mind. Something he should do. flesh-colored instead of the parchment yellow to which he had become accustomed. He closed his mind to the fact that he was sleeping for hours on end like the proverbial baby, and that he was getting such an appetite that he could almost relish even that detestable mush they sent him for breakfast. He was determined to be furious. As soon as he could wake up enough to be. Harper had guessed right. Gleefully from the doorway of his new room suave lobby. shared his self control. The clerk was the first to recover from the collective stupor. "Call them off!" snarled Harper. "Call them off or I'll ruin your Brushing aside the startled secretary in the outer cubicle, Harper "Don't 'my-good-man' me!" snapped Harper. He glared back at the 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. So—Operation Robot is about to bankrupt the syndicate." Placidly Harper puffed a smoke ring. "Of course, you'd have to take into consideration that it would be an experiment for me, too. And there's the suit I'm clearly justified in instituting. However, I'm Harper gazed out at the stunned audience. This was more like the And indeed, Harper was stepping briskly downward, looking spry and fit and years younger. He came across to them actually beaming. It was the first pleasant expression they had seen on his face in years. 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 Harper's smile vanished. "Don't even mention such a thing!" he yelped. turned to his relatives. "Busy day ahead. See you later, folks—" "Same old Harp," observed Scribney. Then he thought of the block of stock. "What say we celebrate our rise to a position in the syndicate,

<question>:
Why did Harper change his tone regarding a vacation to Mars?

<options>:
A He wanted to see the beautiful Emerald Star hotel.
B He was worried about the robots staffing the hotel.
C Bella convinced him he could benefit from some curative rest and relaxation.
D He realized he could profit from a scientific breakthrough.

<answer>:

D