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

<passage>:
That's what they'd better get." Tommy swallowed hard. "And if it happens to be six Grdznth problem getting to be a PRoblem, need expert icebox salesman to get gators out of hair fast. Yes? Math boys hot on this, citizens not so hot. Please come. Not that he didn't like Tommy. Tommy was a good PR-man, as PR-men go. He just didn't know his own depth. PRoblem hoarsely. "Do you hear me? If they aren't going to have their babies in five months, we're dead men." Charlie chuckled. "Five months, he says. We figured the that except in passing. Should have, though, long ago. Two completely independent universes, obviously two energy systems. Incompatible. We were dealing with mass, space and dimension—but the energy differential was the important one." upset the balance, distorted our whole energy pattern. And they knew from the start that the differential was all on their side—a million of them unbalances four billion of us. All they needed to overload us completely was time for enough Tommy's PR-blasts had declared emphatically—but with one When?" "Any day now. Maybe any minute." Charlie spread his telling me. Mean temperature in only 39 below zero, lots of good clean snow, thousands of nice jagged mountain peaks. "For them," Charlie said. Transcriber's Note: that the U.S. copyright on this publication was renewed. Minor spelling and typographical errors have been corrected without note. ?" "I'm afraid so, friend." The Grdznth looked at him reproachfully. "The Wives, of course. The climate is so much better, and they mustn't be disturbed, you know." hordes of indignant citizens. "So I hear," he said. "How many more of you are coming through?" "Oh, not many, not many at all. Only the Wives—half a million or so—and their spouses, of course." The creature clicked his talons nervously. "We haven't much more time, you rumble rose around him like a wave. He was a Public Relations man to the core—but right now he was off duty. He The lobby of the Public Relations Bureau was swarming like fought his way past scurrying clerks and preoccupied poll-takers "Check." "To people who don't want to buy them, right?" "In a manner of speaking," said Pete testily. "Exactly," said Tommy. "Considering some of the movies the papers, but there have been some incidents. Didn't hurt they've been known to be wrong." "And the appointed time?" Tommy spread his hands helplessly. "If we knew, you'd still be in L.A. Roughly six months and four days, plus or minus a month for the time differential. That's strictly tentative, according to the math boys. It's a parallel universe, one of several thousand already explored, according to the Grdznth scientists working with Charlie Karns. Most of the parallels are analogous, and we happen to be analogous to the Grdznth, a point we've omitted from our PR-blasts. They have an eight-planet system around a hot sun, and it's going to get lots hotter any day now." Pete's eyes widened. "Nova?" "Apparently. Nobody knows how they predicted it, but they through parallel after parallel trying to find one they can migrate to. They found one, sort of a desperation choice. It's cold and arid and full of impassable mountain chains. With an uphill fight they can make it support a fraction of their population." the new parallel as fast as possible. The males were picked for brains, education, ability and adaptability the females were chosen largely according to how pregnant they were." Pete grinned. "Grdznth in utero. There's something poetic about it." that climate, at least not until they've been there long enough to get their glands adjusted. Seems we have just the right climate masses, why did we let them in here in the first place?" He Karns'll tell you why." Charlie Karns from Math Section was an intense skeleton of box. "It's the parallel universe business, of course," he said to According to our figuring, this must involve complete control of mass, space and dimension, all three. And time comes into one of the three—we aren't sure which." The mathematician set the black box on the desk top and spin. "No wires?" " Strictly weeks with their top mathematicians, him and a dozen others. How many computers have you burned out, Charlie?" "Four. There's a differential factor, and we can't spot it. They have the equations, all right. It's a matter of translating them into constants that make sense. But we haven't cracked the differential." "And if you do, then what?" Charlie took a deep breath. "We'll have inter-dimensional control, a practical, utilizable transmatter. We'll have null-gravity, which means the greatest advance in power utilization since fire was discovered. It might give us the opening to a "We'll also know the time-differential," said Tommy hopefully, "and how long the Grdznth gestation period will be." "It's a fair exchange," said Charlie. "We keep them until the girls have their babies. They teach us the ABC's of space, mass and dimension." Failed!" The Grdznth sitting on the stool looked regretfully from the cosmetician to the Public Relations men. "I say—I "You should see the field reports. We've tried selling the advances Earth will have, the wealth, the power. No dice. The man on the street reads our PR-blasts, and then looks up to see "How about the 'jolly company' approach?" as it is. And they don't do anything about it. They apologize profusely, but they keep coming through." The two started on for the office. "Things are getting to the breaking point. icy edge to his voice. "You may not have heard about it yet, but you can take my word for it. I personally will be delighted can manage to do excellent PR-man." "Indeed," said Pete. "Tommy, how fast can you get a PR-blast There's one thing they are though, at least half of them." Tommy's jaw sagged. "Pregnant," he said. man in the street reveres, my friend, it's motherhood. We've put together a PR-blast that will twang the people's heart-strings like a billion harps." baby Grdznth are lovable?" sanctity of Grdznth motherhood, my friend, anything goes." "It's genius," chortled Tommy. "Sheer genius." The planning revealed the mark of genius. Nothing sudden, harsh, or crude—but slowly, in a radio comment here or a newspaper story there, the emphasis began to shift from were a trifle overbearing in their insufferable couldn't turn expectant mothers out in the rain. thinner and thinner, while Pete nursed sharp post-prandial Now listen: we need a special run on all response data we have for tolerance levels. Got that? How soon can we have it?" Analysis shook his head. "We could only make a guess with the data so far." "Fine," said Tommy. "Make a guess." "Give us three hours," said Analysis. "You've got thirty minutes. Get going." seeing what the Grdznth are giving us, they'll welcome them with open arms." "Well, why won't they? The people just didn't trust us, that was all. What does the man in the street know about transmatters? we're standing in this for Charlie and his gang to crack the puzzle, time for the Grdznth girls to gestate. But what are we hearing from Charlie?" "That's right," said Pete. " Nothing is what we're hearing from Charlie. We've got no transmatter, no null-G, no power, are giving us." "Well, they can't gestate forever." "Maybe not, but I still have a burning desire to talk to Charlie. Something tells me they're going to be gestating a

<question>:
What did the PR men cause?

<options>:
A The end of the human race
B Empathy for the Grdznth
C A solution to senator Stokes' problem
D All answers are correct

<answer>:

D