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

<passage>:
One: The beacon was repaired. I have a little job I know you’ll enjoy. Repair job. The Centauri beacon has shut down. It’s a Mark III beacon.…” “ What kind of beacon?” I asked him. I have repaired hyperspace beacons from one arm of the Galaxy to the other and was sure I had worked on every type or model made. But I had never heard of this kind. “I never heard of it either until Records dug up the specs. They found them buried in the back of their oldest warehouse. This was the earliest type of beacon ever built—by Earth, no less. Considering its location on one of the Proxima Centauri planets, it might very well be the first beacon.” I looked at the blueprints he handed me and felt my eyes glaze with horror. “It’s a monstrosity! It looks more like a distillery than a beacon—must be at least a few hundred meters high. I’m a repairman, not an archeologist. This pile of junk is over 2000 years old. Just forget about it and build a new one.” The Old Man leaned over his desk, breathing into my face. “It would take a year to install a new beacon—besides being too expensive—and this relic is on one of the main routes. We have Forty-four on Company Duty and My Troubles. “This department is officially called Maintenance and Repair, when it really should be called trouble-shooting. Hyperspace beacons are made to last forever—or damn close to it. When one of them breaks down, it is the repairs. I have to browbeat, bribe, blackmail and bulldoze you thugs into doing a simple job. If you think you’re fed up, just think how I feel. But the ships must go through! The beacons must operate!” By the time the ship was serviced, I had a course charted. The nearest beacon to the broken-down Proxima Centauri Beacon was on one of the planets of Beta Circinus and I headed there first, a short trip of only about nine days in hyperspace. To understand the importance of the beacons, you have to understand hyperspace. Not that many people do, but it is easy enough to understand that in this measurements are a matter of relationship, not constant facts like the fixed universe. The first ships to enter hyperspace had no place to go—and no way to even tell if they had moved. The beacons solved that problem and opened the entire universe. They are built on planets and generate tremendous amounts of power. This power is turned into radiation that is punched through into hyperspace. Every beacon has a code signal as part of its radiation and represents a measurable point in hyperspace. Triangulation and quadrature of the beacons works for navigation—only it follows its own rules. The rules are complex and variable, but they are still rules that a navigator can follow. For a hyperspace jump, you need at least four beacons for an accurate fix. For long jumps, navigators use as many as seven or eight. So every beacon is important and every one has to keep operating. That is where I and the other trouble-shooters came in. We travel in well-stocked ships that carry a little bit of everything overly efficient repair machinery. Due to the very nature of our job, we spend most of our time just rocketing through normal space. After all, when a beacon breaks down, how do you find it? Not through hyperspace. All you can do is approach as close as you can by using other beacons, then finish the trip in normal space. This can take months, and often does. This job didn’t turn out to be quite that bad. I zeroed on the Beta Circinus beacon and ran a complicated eight-point problem through the navigator, using every beacon I could get an accurate fix on. The computer gave me a course with an estimated point-of-arrival as well as a built-in safety factor I never could eliminate from the machine. the time. I was asleep when the alarm went off that announced planetary distance. Planet two, where the beacon was situated according to the old charts, was a mushy-looking, wet kind of globe. I tried to make sense out of the ancient directions and finally located the right area. Staying beacon, equidistant on a line between two of the most prominent mountain peaks. I located the peaks easily enough and started the eye out from the first peak and kept it on a course directly toward the second. There the beacon appear on the screen. The image blinked, focused—and a great damn pyramid swam into view. I cursed and wheeled the eye in circles, scanning the surrounding in a ten-mile circle was this pyramid—and that definitely wasn’t my beacon. Or wasn’t it? I dived the eye lower. The pyramid was a crude-looking thing of Locking the eye in a circular course, I dug through the Mark III plans—and there it was. The beacon had a precipitating field and a basin on top of it for water this was used to cool the reactor that powered the monstrosity. If the water was still there, the beacon was still there—inside the pyramid. The natives, who, of course, weren’t even mentioned by the idiots who constructed the thing, had built a nice heavy, thick stone pyramid around the beacon. I pulled the eye straight up and away and threw in the control circuit that would return it automatically to the ship. Then I went to the galley for a long, strong drink. My beacon was not only locked inside a mountain of handmade stone, but I had managed to irritate the things who had built the pyramid. A great beginning for a Anthropologists may not mind being dissected for their science, but a repairman wants to make no sacrifices of any kind for his job. For this reason, most beacons are built on uninhabited planets. If a beacon has to go on a planet with a culture, it is usually built in some inaccessible place. Why this beacon had been built within reach of the local claws, I had yet to find out. But that would come in time. The first thing to do was I learned all I needed to know of the history, past and recent, and it wasn’t nice. In addition to the pyramid being around the beacon, there was a nice little religious war going on around the pyramid. It all began with the land bridge. Apparently the local lizards had been living in the swamps when the beacon was built, but the builders didn’t think much of them. They were a low type and confined to a distant continent. The idea that the race would develop and might reach this continent never occurred to the beacon mechanics. Which is, of spot, and the lizards began to wander up beacon valley. And found didn’t hurt the natives. It caused mutations that bred true. A city was built around the temple and, through the centuries, the pyramid was put up around the beacon. A special branch of the priesthood served the temple. All went well until one of the priests violated the could have had a lizard fry, fixed the beacon and taken off. Only “native life-forms” were quite well protected. There were spy cells on my ship, all of which I hadn’t found, that would A crumbling and cracked stone stairway brought us up to a solid metal doorway labeled in archaic script MARK III BEACON—AUTHORIZED PERSONNEL ONLY . The trusting builders counted on the sign to do the lizard merely turned the handle and we were inside the beacon. I unzipped the front of my camouflage suit and pulled out the blueprints. With the faithful priests stumbling after me, I located the the emergency batteries, just enough to give a dim light. The meters and rest of the beacon. In 2000 years, there should be some the beacon door when I woke up. A delightful prospect, eternity spent in a locked beacon with three

<question>:
Why are the beacons important?

<options>:
A Ships travel through beacons in hyperspace.
B Beacons are religious focal points for natives.
C They aren't; ships can travel without them.
D Beacons are like landmarks or stars for ships to use in navigation.

<answer>:

D