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 _. Your answer should be chosen from the given text, and should not contain other words.

[EX Q]: Aaron Hotchner: There have been two known copycats .
Penelope Garcia: Correct . The first _ one _ was Heriberto Seda . He killed three and wounded four in New York City . And then , there was a 14-year - old in Japan named Seito Sakakibara . He killed two other children and left the sign of the Zodiac behind .
David Rossi: The fact is the Zodiac was driven by a need for notoriety and control .
Aaron Hotchner: He enjoyed the terror he spread through the city .
[EX A]: copycats

[EX Q]: The Doctor: Those shields wo n't hold them there for long .
Briggs: They 'll last until we 're back to Earth .
The Doctor: And then ?
Briggs: There 's only a few of them : our security men will cope with them .
The Doctor: They 're an invasion force , Earth is where they want to go . There are considerably more than a few on board .
Adric: How many of these silos are you carrying ?
Briggs: Oh , _ fifteen _ thousand or ...
Briggs: No
Briggs: . It 's not possible !
[EX A]: silos

[EX Q]: Wizard - Host: It was a time of chaos . The unstoppable Cragmite empire wreaked havoc across the galaxy until a race of unlikely heroes fought back : the Lombaxes , who may be some sort of lemur - wombat .
Boomstick - Host: Well , whatever they are , they 're pretty good at kicking the shit out of Cragmites and ended up stopping the empire by banishing them to another dimension . Well , all except one and boy , would that come back to bite 'em in the ass !
Wizard - Host: Raised as one of their own , the last Cragmite betrayed his foster Lombaxes , raised an army of fish people , and , in some sense of cruel ironic justice , banished the entire Lombax race to their own dimension as well . And , just as ironically , missed one who would prove to be his greatest adversary .
Boomstick - Host: This lone Lombax 's name was Ratchet , and he spent most of his days stranded on a random planet , dicking around with mechanical stuff , and dreaming of one day exploring the galaxy . So , this alien ... kitty cat ... thing scrounged up all the scraps he can find , used his natural gift with machines , and built a space ship so incredible , it would finally take him off this boring planet once and for ...
Boomstick - Host: ...
Boomstick - Host: all .
Wizard - Host: Without an onboard robot ignition system , this hunk of junk would never fly .
Boomstick - Host: And with Ratchet 's luck , it 's not like _ one _ was just gon na drop out of the sky or something .
Boomstick - Host: Well
Boomstick - Host: , I 'll be damned .
Wizard - Host: This was the sentry bot serial number XJ-0461 .
Boomstick - Host: But that 's hard to say in conversation , and he makes a clanky sound when he falls over , so ...
Clank: Maybe I 'll just call ya ... Clank .
Wizard - Host: Clank had just been assembled maybe half an hour earlier , and was already running for his life .
Boomstick - Host: Yeah , see , he came from a robot killing machine making factory , but when the factory malfunctioned and made this little guy , it decided to scrap him for parts . So , naturally , he got the hell out of there , ended up with Ratchet , and together they became the greatest hero duo in the galaxy .
[EX A]:
system