GWD-16-14

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.

1. the numbers of tucks alone
2. that number of trucks alone
3. the number of trucks by themselves
4. as many trucks themselves
5. as many trucks by themselves

应该选什么呢,请高手指教

B

A numbers        OUT

C  by themselves  感觉不妥

还是用that number指代清楚