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

<passage>:
The Gravity Business By JAMES E. GUNN "Now Fweep ain't the brightest creature in the Universe, so he can't Illustrated by ASHMAN rocked unsteadily on its flat stern before it decided to stay upright. reflexes, he sat in the pilot's chair, the control stick between his knees, his thumb still over the Off-On button on top. "I know it, Fred," he said, frowning. "This world fooled me. It has a diameter less than that of Mercury and yet a gravitational pull as great as Earth." Grampa started to say something, but an 8-year-old boy looked up from Junior, that's why we picked this planet. We fed all the orbital data into Abacus, and Abacus said that orbital perturbations indicated that the second planet was unusually heavy for its size. Then Fred said, 'That looks like heavy metals', and you said, 'Maybe uranium—'" "That's enough, Four," Junior interrupted. "Never mind what I said." somehow ice water had replaced the warm blood in her veins. "I'm sure he did the best he could." "Anybody talks about gravitational pull," Grampa said, snorting, "deserves anything anybody could say about him. There's no such thing, Junior. You ought to know by now that gravitation is the effect of the curving of space-time around matter. Einstein proved that two hundred years ago." "Go back to your games, Grampa," Fred said impatiently. "We've got work bought it?" "You bought it, Grampa," Fred said. "That's right! And who invented the gravity polarizer and the space flivver? Eh? Who made possible this gallivanting all over space?" "You, Grampa," Fred said. "Look!" he said suddenly. "This planet not only has flora—it has "Four!" Reba called out warningly. "It's all right, Reba," Four assured her. "The air is within one per cent of Earth-normal and the bio-analyzer can find no micro-organisms viable within the Terran spectrum." won't budge!" The thing was a featureless blob, a two-foot sphere of raspberry aliens. And that's nothing but a—a blob!" regal and slim. The pose was spoiled immediately by her avid question: "Any uranium? Radium? Thorium?" "No," Fred said slowly, "and no other heavy metals, either. There's a few low-grade iron deposits and that's it." "Then what makes this planet so heavy?" Reba asked. Junior shrugged helplessly and collapsed into a chair. "Your guess is as good as anybody's." "We've still got Fweepland," Four said solemnly. "Fweepland?" Reba repeated. "This planet. It's not big, but it's fertile and it's harmless. As real estate, it's worth almost as much as if it were solid uranium." "A good thing, too," Junior said glumly, "because this looks like the it's broken or there's something about the gravity around here that just won't polarize." "It's these '23 models," Grampa put in disgustedly. "They never were spaceship rested on its improbable stern. The sixteen Earth hours that the rotation had taken had changed nothing inside the ship, either. If we get back to Earth," he amended. "You can't be Four's father. All over the Universe, gravity is the same, and if it's gravity, the polarizer will polarize it." "That's just supposition," Junior said stubbornly. "The fact is, it isn't because it doesn't. Q.E.D." recirculation systems are going, the food resynthesizer is okay. And, of polarization itself. For some reason, it doesn't work here. Why? what's the theory behind polarization?" or ellipses." The faces were still blank and unillumined. "Gravity is similar to light," he pressed on. "In the absence of matter, gravity is non-polarized. Matter polarizes gravity in a circle around itself. That's how we've always known it until the invention of spaceships and later the polarizer. The polarizer polarizes gravity into a straight line. That makes the ship take off and continue accelerating until the polarizer is shut off or its angle is shifted." perpetual-motion machines and those crazy longevity schemes when any moron would know they were impossible." Grampa squinted at her sagely. "That's what they said about the gravity polarizer before I invented it." "But you don't really know why it works," Junior persisted. "And make the best of what we've got," Reba went on, unheeding. "If we look at it the right way, it's quite a lot. A beautiful, fertile world. Earth gravity. The flivver—even if the polarizer won't work, there's the resynthesizer it will keep us in food and clothes for years. By carrying a curious contraption made of tripod legs supporting a "Where've you been?" Reba asked anxiously. "What've you been doing?" "I've been all over Fweepland," Four said wearily, "trying to locate its center of gravity." "Well?" Fred prompted. "It shifts." "He's why the flivver won't work. What Grampa invented was a linear polarizer. Fweep is a circular polarizer. He's what makes this planet so heavy. He's why we can't leave." The land of the Fweep rotated once on its axis, and Grampa lowered unbelievingly. something with him. It's preposterous that we should be detained here at the whim of a mere blob!" "I don't figure it's a whim," Grampa said. "Circular gravity is what he's got to have for one reason or another, so he just naturally bends the space-time continuum around him—conscious or subconscious, I don't know. But protoplasm is always more efficient than machines, so the "I don't care why that thing does it," Joyce said icily. "I want it stopped, and the sooner the better. If it won't turn the gravity off, we'll just have to do away with it." "How?" asked Four. "Fweep's skin is pretty close to impervious and he 'eats' everything. And violence might be more dangerous to us than to him. Right now, Fweep is friendly, but suppose he got mad! He could lower his radioactive shield or he might increase the gravity by a few times. kind on this planet." something. He couldn't just have sprung into being as he is now." "Maybe he developed," Four offered. "It seems to me that he's bigger than when we first landed." "He must have been here a long, long time," Fred said. "Fweepland, as Four calls it, kept its atmosphere and its water, which a planet this size ordinarily would have lost by now." making us think the planet had heavy metals and I want him to let us go immediately !" "Makes you think, doesn't it?" Grampa said, looking at Fweep benignly. "Maybe the whole theory of gravitation is cockeyed. Maybe there's a Fweep for every planet and sun, big and little, polarizing the gravity in circles, and the matter business is not a cause but a result." "What I can't understand," Junior said thoughtfully, "is why the "Linear polarization is uncomfortable for him, is it?" Grampa said. "He's no more improbable than people," said Four. Four is strange enough without encouraging him to think like a martyr. it's a simple problem in logic. It's a pircuit problem, like the one about Fweep won't let our polarizer work. He won't let our polarizer work because he doesn't like gravity that's polarized in a straight line, and he don't want Four to leave him.

<question>:
Why is gravity on the planet abnormal?

<options>:
A There is much more gravity than Earth
B It has polarized gravity
C It is not the straight-line kind of gravity
D There is much less gravity than Earth

<answer>:

C