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

<passage>:
TOWER By EVELYN E. SMITH As the vastly advanced guardians of mankind, the Belphins knew how to make a lesson stick—but whom? others composing symphonies Me! Only the Belphins were much in evidence. Only the Belphins had duties to perform. Only the Belphins worked. But they won't pay any attention to me!" Courteous, like all members of his species, the creature leaped from the street and listened attentively to the young man's question. "We Belphins have but one like and one dislike," he replied. "We like what is right and we dislike what is wrong." "That was good of you." She continued in a warmer tone: "How many Belphins did you warn, then?" "That's just theory," she said. "It's never been proven. All we do know is that they have some sort of central clearing house of information, presumably The Belphin of Belphins. But we don't know that they are incapable of thinking or acting individually. We don't really know much about them at all ," the Belphin said, gazing reverently across the city to the blue spire of the tower where The Belphin of Belphins dwelt, in constant communication with every member of his race at all times, or so they said. "That is why we were placed in charge of humanity. Someday you, too, may advance to the point where you "You must warn as many Belphins as you can." "But "Then," she said dramatically, "you must approach The Belphin of Belphins himself." who The Belphin. You're coming to A lifetime spent under their gentle guardianship had made Ludovick able to interpret the expression that flitted across this Belphin's frontispiece as a sad, sweet smile. the Belphins surrender their secrets to gratify the idle curiosity of a poet? "He'd only make another. Don't you see, Ludovick, this is our only chance to save the Belphins, to save humanity.... But, of course, I don't have the right to send you. I'll go myself." Next morning, he set out to warn Belphins. He knew it wasn't much use, but it was all he could do. The first half dozen responded in much the same way the Belphin he had warned the previous day had done, by courteously acknowledging his solicitude and assuring him there was no need for alarm After that, they started to get increasingly huffy—which would, he thought, substantiate the theory that they were all part of one vast coordinate network of identity. Especially since each Belphin behaved as if Ludovick had been repeatedly annoying him . It was not that griping was illegal, for the Belphins permitted free speech and reasonable conspiracy "I must see The Belphin of Belphins. I must warn him against the Flockharts." "I don't trust you or your brothers. I must see The Belphin himself." Suddenly this particular Belphin lost his commanding manners. He began to wilt, insofar as so rigidly constructed a creature could go limp. "Please, we've done so much for you. Do this for us." "The Belphin of Belphins did things for us," Ludovick countered. "You are all only his followers. How do I know you are grandfather told me that, when the Belphins took over Earth, they rewrote all the textbooks to suit their own purposes. Now nothing but Belphin propaganda is taught in the schools." "Please, young man——" the Belphin began. "You don't understand. Let me explain." Ludovick smiled and set his nearly full glass down on a plinth. "You could hardly call the Belphins foreigners When he came to, most of the vapor had dissipated. The Belphin of Belphins was already dying of asphyxiation, since it was, in fact, a single alien entity who breathed another combination of elements. The room at the head of the stairs had been its tank. The uncle sat up and wrapped his arms around his thick bare legs. He was a powerful, hairy brute of a creature who had not taken advantage of the numerous cosmetic techniques offered by the benevolent Belphins. "Don't you think it's funny they can breathe our air so easily?" "They say," the uncle continued, impervious to Ludovick's unconcealed dislike for the subject, "that there's really only one Belphin, who lives in the Blue Tower—in a tank or something, because he can't breathe our atmosphere—and that the others are a sort of robot he sends out to do his work for him." "Nonsense!" Ludovick was goaded to irritation at last. "How could a robot have that delicate play of expression, that subtle economy of movement?" Shortly after The Belphin's demise, the Flockharts arrived en masse. "We won't need your secret weapons now," Ludovick told them dully. "The Belphin of Belphins is dead." Corisande and the uncle exchanged glances. "But they are absolutely blank," the uncle began hesitantly. "Perhaps, with your rich poetic imagination...." "Even if The Belphin is a single entity," Ludovick went on, "that doesn't necessarily make him less benevolent——" The Belphin of Belphins died in Ludovick's arms. He was the last of his race, so far as Earth was concerned, for no more came. If, as they had said themselves, some outside power had sent them to take care of the human race, then that power had given up the race as a bad job. If they were merely exploiting Earth, as the malcontents had kept suggesting, apparently it had proven too dangerous or too costly a venture. "See?" old Osmond remarked with satisfaction. "The kid's brain-washed. I told you so." were my secret weapon all along!" She beamed at her "relatives," and it was then he noticed the faint lines of her forehead. "I told you I could use the power of love to destroy the Belphins!" And then she added gently: "I think there is no doubt who is head of 'this family' now." "Of course they have their own source of power," Ludovick informed them, smiling to himself, for his old Belphin teacher had taken great care to instill a sense of humor into him. "A Belphin was explaining that to me only today." Ludovick looked at him through a haze of tears. "But I killed The Belphin. I didn't mean to, but ... they must hate me!" "He said the Belphins rule through the power of love." anarchists ." subversives ?" on the other hand, could he stand idly by and let those neighbors attempt to destroy the social order? Deciding that the greater good was the more important—and that, moreover, it was the only way of taking Corisande away from all this—he went in search of a Belphin. That is, he waited until one glided past and called to him to leave the walk. The Belphin appeared to think for a minute. Then he gave off a smile. "Oh, them," he said. "We know. They are harmless." force !" Ludovick knew, of course, that the Belphin used the word metaphorically, that the Tower was protected by a series of highly efficient barriers of force to repel attackers—barriers which, he realized now, from the sad fate of Mieczyslaw and George, were potentially lethal. However, he did not blame the Belphin for being so cagy about his race's source of power, not with people like the Flockharts running about subverting and whatnot. "You suggest that we try to turn the power of love against the Belphins?" the uncle asked ironically. He lay down to sleep that night beset by doubts. If he told the Belphins about the conspiracy, he would be betraying Corisande. As a matter of fact, he now remembered, he

<question>:
Who are the Belphins?

<options>:
A The royal family.
B Politicians
C An alien race
D Robots

<answer>:

D