Teacher: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. There are several possible answers, you'll need to choose the proper one. Carefully read the given text, pay special attention to the marked number, think about what (unwritten) information the marked number holds inside, choose the most adequate word(s) from the optional answers. If none of them seems right to you, there's also an option for other. If your answer is "REFERENCE", also write the reference entity, otherwise write the implicit option name. Options to choose from are:
REFERENCE: Some object which is being mentioned in the text before or after the target number. The reference answer has a higher priority than any other. If both Reference and another answer are possible, prioritize the Reference.
YEAR: Describing a calendric year
AGE: Describing someone's age
CURRENCY: Reference to some monetary value e.g dollar, euro etc.
PEOPLE: Describing a single/plural persons
TIME: Describing a time of the day. Usually you can add the word o'clock after those numbers.
OTHER: Some other option, which isn't listed here.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Jess Mastriani: No, I don't want another crooler, thank you very much.
 FBI Agent Nicole Scott: But it's good for you. It's got... honeyglaze. Please die for this crooler, Jess.
 Jess Mastriani: I've had _ two _ already. Who eats three croolers in a night? 
FBI Agent Nicole Scott: Take a look. [Nicole takes a huge bite] Mmmmm, Mmmmm, Mmmmm!
Solution: REFERENCE crooler
Reason: In this example, the number two refers to something that appears in this text. In this example, it refers to the word: crooler.

Now, solve this instance: Master Roshi:  The legend , as I was told , goes something like this : In the beginning , there was only one Dragon Ball . It was huge , I mean REALLY huge . It had to be - it held all of the mystical energies of the universe . An ancient tribe discovered it , and was inspired by its magnificent power . They built a shrine around it , and protected the orb by placing it in the mouth of a giant dragon statue , said to be its eternal guardian . You should have seen the detail on this thing . It was INCREDIBLE : scales made of ruby , teeth of pearl ... Speaking of pearl , they say there was this one native girl ...
Bulma: GET ON WITH IT !
Master Roshi: Yes , well ... The tribe enjoyed years of prosperity , until one day : evil paid a visit to the village in the form of a band of thieves . These agents of darkness stormed the temple in an attempt to steal the Dragon Ball for their own selfish gain . They were shocked to discover the true power of the Ball . To ensure such an attack never happened again , the Dragon Ball was divided into seven smaller orbs , and scattered across the globe . Separately , the Dragon Balls were useless , but when all _ seven _ were united , then a single voice could summon the Eternal Dragon for one wish , and one wish only . Some wishes were pure , but others were tainted by blind ambition . This led to pain and suffering , as an unjust few wished for power and dominion over mankind . But , as the story goes , there will one day come a hero who will use the Dragon Balls for goodness , and bring peace and unity to the world once more .
Student:
REFERENCE Balls