急~各位牛人帮我看看这道语法题吧！！！

s19870117

GWD-12-Q14:

In 1914 a total of 469,000 cars and trucks were produced in the United States
, but in 1929 almost twice the numbers of tucks alone came off the assembly lines.


A.the numbers of tucks alone

B.that number of trucks alone

C.the number of trucks by themselves

D.as many trucks themselves

E.as many trucks by themselves

请教，答案是B，that在这里是什么成分啊，引导定语从句吗？

s19870117

我补一下，是不是that number指代469,000，意思是1929年仅truck自己的产量就是这个数字的两倍。

700700700

恩 同意楼主的意思 that number 感觉就是指的之前那个数据

s19870117

恩恩！谢谢~脑残了我，一看见that就想定语从句，最基本的指示代词功能都以为是错的。。。。。