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

<passage>:
only in Centurian humanoids, not Earth-norm human beings. Which are What is Doc's full name? I looked at that which he had made. I wondered where he had gone, in search of what. So I was an Earthman, Doc's son. So my addiction to coffee was all in thing greasy collar of the human. absurd, easy lie. "Old events seem recent to him." The human nodded, Adam's apple jerking in the angry neon twilight. "'Memory Jump,' you mean. All my great-grandfathers have it. But Great-great-grandmother Lupos, funny thing, is like a schoolgirl. or the Necronomican itself on human beings?" "Exactly, Kevin, exactly. They have never existed any more than your Victorian detective friend. But the unconscious racial mind has reached back into time and created them. And that unconscious mind, deeper than psychology terms the subconscious, has always known about the powers of ESP, telepathy, telekinesis, precognition. Through these books, aliens . They weren't men the human race can tell itself how to achieve a state of pure logic, Martians. They were state of pure thought." "The North American government has the inhabited universe, but reason finally prevailed. He had reached a girl said. "You can't let it fall into the hands of the Martians." Andre did not deny that he wanted it to fall into his hands. I knew I could not let Doc's—Dad's—time travel thing fall into to have this secret, Kevin," the thing it because I didn't want the human race to become a thing of pure reason without purpose, kick the habit—perhaps with Miss Casey's help—but I wasn't really confident. Maybe I had destroyed the time machine because a world without material "You don't have any nickel. You don't have any quarter, not if I say jagged cut-out nude curled against a lump of dust and lint, giving it suddenly distinguishable. " Outsider ... Thoth ... ... Oh, are that these like Doc and me. lumpy skull. perhaps, as a teacher or supervising telephone operator. "Do you want it for coffee, or to apply, or a glass or hypo of something else?" call her that. "A little more for food, if you could spare it." whatever. tourist . "Now what do you want to eat?" the woman asked. I didn't look at her. She didn't know. She thought I was a human—an Earth human. I was a man , of course, not an alien like a Martian. Earthmen ran the whole Solar Federation, but I was just as good as an Earthman. With my suntan and short mane, I could pass, couldn't I? That proved it, didn't it? "Hamburger," I said. "Well done." I knew that would probably be all they had fit to eat at a place like this. It might be horse meat, but without food, without sex, without conflict—just as Doc has achieved "It's Miss Casey—Vivian Casey," she corrected. She was a a name, "What do you think of this?" I looked at the piece of paper. It was a coupon from a magazine. : Please send me FREE of obligation, in sealed wrapper, "The Scarlet Book" revealing to me how I may gain Secret Mastery of the Universe. Name thing knew this last time had been Doc had ever made anything. It didn't look like much, but it was a dissolved under his touch. All of them, useless parts, were made into a meaningful whole. I knew the thing had meaning, but when I tried to follow its design, I He held something out to me. It was my notebook. He had used my pen, I wondered what the words meant. Wondering takes a kind of familiar with Earth history and I recognized the period immediately. Then I realized what I had been trying to get from Doc all these months—time travel. A thin, sickly man was sprawled in the other chair in a rumpled dressing gown. My eyes held to his face, his pinpoint pupils and hated or held in more contempt than tourists or Martians, it was a snowbird. "My clients have occasioned singular methods of entry into these rooms," the thin man remarked, "but never before have they used instantaneous materialization." The heavier man was half choking, half laughing. "I say—I say, I would like to see you explain this, my dear fellow." this unemployed, former professional man who has gone through a serious illness and is suffering a more serious addiction to tell me the place and time from which he comes." The surprise stung. "How did you know?" I asked. He gestured with a pale hand. "To maintain a logical approach, I must reject the supernatural. Your arrival, unless hallucinatory—and despite my voluntary use of one drug and my involuntary experiences recently with another, I must accept the evidence of my senses or retire from my profession—your arrival was then super-normal. I might say super-scientific, of a science not of my or the good doctor's time, clearly. Time travel is a familiar folk legend and I have been reading an article by the entertaining Mr. Wells. Perhaps he will expand it into one of his novels of scientific romance." other—" state?" He was so smug and so sure, this snowbird. I hated him. Because I couldn't trust to my own senses as he did. "You don't exist," I said slowly, painfully. "You are fictional creations." The doctor flushed darkly. "You give my literary agent too much credit for the addition of professional polish to my works." The other man was filling a large, curved pipe from something that looked vaguely like an ice-skate. "Interesting. Perhaps if our visitor would tell us something of his age with special reference to the theory and practice of temporal transference, Doctor, we would be better equipped to judge whether we exist." There was no theory or practice of time travel. I told them all I had ever heard theorized from Hindu yoga through Extra-sensory Perception to Relativity and the positron and negatron. "Interesting." He breathed out suffocating black clouds of smoke. "Presume that the people of your time by their 'Extra-sensory Perception' have altered the past to make it as they suppose it to be. the goddesses of love that people imagined or the scrawny, big-nosed unknown sort to me. His tapered fingertips had indented the metal. a snowbird. After a time, I asked the doctor a question. My heart raced, but I saw something dancing before me like a dust mote It exists. It's real. Not even one of the unwritten ones. I've read was something else. "I just want a drink of coffee from that container on the chair," I told her. She shook her head. "I don't know what you think it does to you." It was getting hard for me to think. "Who are you?" She showed me a card from her wrist purse. Vivian Casey, Constable, North American Mounted Police. I had to help Doc. I had to have some coffee. "What do you want?" "Listen, Kevin. Listen carefully to what I am saying. Doc found a method of time travel. It was almost a purely mathematical, topographical way divorced from modern physical sciences. He kept it secret and he wanted to make money with it. He was an idealist—he had his crusades. How can you make money with time travel?" I didn't know whether she was asking me, but I didn't know. All I knew was that I had to help Doc and get some coffee. thing "Call me Andre," the Martian said. "A common name but foreign. It should serve as a point of reference." I had always wondered how a thing like a Martian could talk. Sometimes I wondered if they really could. "I'll keep it, thanks. What do want?" "They ceased to exist—as human beings—shortly after they received a "Use one of those sneaky Martian weapons again," I warned him, "and I'll kill the girl." Martians were supposed to be against the that dirty." thing

<question>:
What is the "thing"?

<options>:
A A state of pure thought.
B A book that doesn't exist.
C A vehicle to find coffee.
D An agent of time travel.

<answer>:

D