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

<passage>:
R X The tenth son of a tenth son was very sick, but it was written that he would never die. Of course, it was up to the Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] ship from HQ in Standard GPP Contract code for crash priority, which Ten minutes later the Red Doctor reached for the results of the Initial "Trouble?" said the squawk-box, sleepily. "Oh, brother," said Jenkins. "Somebody's cracked the Contract Code or the control room, rubbing his eyes. "What happened?" he said. "We've changed course." "Sounds familiar, but I can't quite tune in. Crash call?" His eye caught the black-striped card. "Class VI planet ... a plague spot! How can we get a crash-call from this ?" "You tell me," said Jenkins. "Wait a minute. Seems to me there was some sort of nasty business—" bodily. The last time an Earth ship landed there half the crew was the folks on Morua II didn't want a Contract with Hospital Earth. And doctors and spells." He tossed the Info-card down the chute with a growl. "So now we have an emergency call from them in a Contract code they couldn't possibly know." The surgeon in the green undershorts chewed his lip. "Looks like going there, are we?" "What else? You know the law. Instantaneous response to any how Morua II got the code, but they got it, and that's all the farther we're supposed to think. We answer the call, and beef about it later. If we still happen to be around later, that is." Contract had been signed with Deneb III centuries before, Hospital whenever and wherever it was required, on any planet bound by Contract. That was the law, for Hospital Earth could not afford to jeopardize a Contract. In the early days of galactic exploration, of course, Medical Services multitudes of planets into social and economic interdependence Other planets outstripped Earth in technology, in communications, in landed, the crew was soon rendering Medical Services of one sort or the Medical Service Contract was formalized, and Hospital Earth came Practice Patrol were dispatched—"Galactic Pill Peddlers" forging a chain of Contracts from Aldebaran to Zarn, accepting calls, diagnosing ills, arranging for proper disposition of whatever medical problems they came across. Serious problems were shuttled back to Hospital Earth more frequently the GPP crews—doctors of the Red and Green services, representing the ancient Earthly arts of medicine and It was a rugged service for a single planet to provide, and it was costly. Many planets studied the terms of Contract and declined, other planets—places such as Morua II.... The Lancet homed on the dismal grey planet with an escort of eight with heavy grey fur ruffing out around their faces like thick hairy dog collars. The one in command strode forward arrogantly, one huge paw leveling a placer-gun with a distinct air of business about it. government. Finally a pair of steel doors opened to admit them to a long, arched hallway. Their leader, who was called Aguar by his flunkies, halted them with a snarl and walked across to the tall figure he wore a long purple cap with a gold ball on the end which twitched wildly as their whispered conference devolved into growling and snarling. Finally Aguar motioned them to follow, and they entered the far chamber, with growled. "Who is His Eminence?" Jenkins asked. rumbled. "He is the Tenth Son of a Tenth Son, and it is written that he can never die. When you enter, bow," he added. illness is this?" he whispered. "He is afflicted with a Pox, as any fool can see. All others it "How should I know? I've never seen a healthy Moruan before, to say nothing of a sick one. It looks like a pox all right." "Probably a viremia of some sort." Jenkins went over the great groaning hulk with inquiring fingers. "If it's a viremia, we're cooked," Stone whispered. "None of the drugs cross over—and we won't have time to culture the stuff and grow any new ones—" Jenkins turned to Aguar. "How long has this gone on?" "For days," the Moruan growled. "He can't speak. He grows hot and is all over. We have heard about you wizards from Hospital Earth. You cure all, the stories say. You are very wise, they say. You balance him. If he didn't die naturally we'd kill him for sure! We can't go near him "Well, we've got a little to go on just from looking at them. They're oxygen-breathers, which means they manage internal combustion of carbohydrates, somehow. From the grey skin color I'd guess at a cuprous or stannous heme-protein carrying system. They're carnivores, but god knows what their protein metabolism is like—Let's get going on some of these specimens Aguar has rounded up for us." send in a full crew of technicians to a newly-Contracted planet to response because of its utter lack of organization. But a creature with an organized central nervous system and a functional division of work among organ systems could be categorized, tested, studied, and ran the X-ray and pan-endoscopic examinations. After four grueling hours the Red Doctor groaned and scowled at the growing pile of data. "Okay. It seems that they're vaguely humanoid. And that's about all we can say for sure. I think we're wasting time. What say we tackle the control room at gunpoint, along with a couple of minor medical potentates. Purple-hat's name was Kiz, and it seemed that he wasn't having any that day. haven't. So you can at least get us started. What kind of course does it run?" Silence. "All right then, what causes it? Do you know? Bacteria? Virus? Degeneration?" Silence. on Kiz. "Of course, that might be right up your alley—how about that? His Eminence bows out, somebody has to bow in, right? Maybe you, huh?" violently on the idea of a Hospital Earth Contract, eh? Couldn't risk won't drive him out." "Won't it, now! Well, we have iron needles bottoms out of their jars. Suppose they drive him out?" Aguar will—" "Maybe not," said Sam. "Look, I've got an idea—risky, but it might promises, pills and post-mortems. That's the Medical service for you." That would open their eyes all right." "No thanks, not me. This is a medical case and it's all yours. What do grimly. "Tell them to send an armada, because we're liable to need one in the next few hours—" this bag of rhythm with the intravenous drip ... and waited. The room was deathly still except for a heavy snuffling sound from His is empty—or if there is any change. Whatever you do, don't touch down on a bench in the hall and fell asleep in an instant. They woke him once, hours later, to change the intravenous solution, Morua is not a Contract planet and we're not supposed to be here in the of parchment, stricken through with the colors of the seven Medical Services of Hospital Earth. "Take a look, my boy—the juiciest Medical Services Contract that's been written in three centuries—" He tossed the Contract in the dry-storage locker with a sigh. "Old Kiz just finished his first lesson, and he's still wondering what went on—" involves fever, starvation and dehydration. I knew that His Eminence could assimilate carbohydrates, and I took a long gamble that an one other prescription to use—the oldest, most trustworthy healer-of-all-ills known to medicine, just as potent now as it was a thousand years ago. Without it, Hospital Earth might just as well pack

<question>:
How many planets have medical service contracts with Earth?

<options>:
A Over one hundred
B About fifty
C One
D Unknown

<answer>:

D