prep的一道题

with a record number of new companies starting up in Derderia and with previously established companies adding many jobs, a record number of new jobs were created last year in hte Derderian economy. this year, previously establish companies will not be adding as many new jobs overall as such companies added last year. therefore, unless a record number of companies start up this year, derderia will not break its record for new jobs created.

which of the following is an assumption on with the argument relies?

b. companies established last year will not add a greater number of jobs overall this year than they did last year
c. this year, the new companies starting up will not provide substantially more jobs per company than did new companies last year

这道题我很大程度上是猜的，选了b，正确答案应该是c。但我既不明白b错在了哪里，也不明白c对在了哪里。哪位大侠可以帮忙解释一下？？谢谢

我不是大侠..说说我的看法

结论是derderia will not break its record for new jobs created.

ASSUMPTION其实就是unless改写,也就是c选,

将c取非今年新公司将提供比去年新公司更多工作机会->weaken结论

B选我觉得它是拿去年成立公司今年与去年工作机会提供比较与结论前提unless a record number of companies start up this year
        不一致

请指教

还是没太明白。。。有那位能在给明白地指点一下么？

已知：
1）去年新成立的公司数量创了记录。2）已经成立的公司增加雇员。=》 去年新增的工作数量创了记录。

已知：
３）今年已经成立的公司增加雇员不会更多。

论点：如果新成立的公司数量比去年少，那么新增的工作数量不会创纪录。

问：论点基于什么假设。
答：每一个今年新成立的公司不会比每一个去年新成立的公司提供更多的工作。　
换句话说，就算今年新成立的公司数量比去年少，如果今年每一个今年新成立的公司比去年每一个新成立的公司提供更多的工作，那么新增的工作数量还是有可能会创纪录的。

这到题考的是：　新增的工作数量＝新成立的公司数量Ｘ平均每一个新成立的公司能提供的工作数量。
用已经成立的公司的雇员数做干扰。

b. companies established last year will not add a greater number of jobs overall this year than they did last year
Ｂ是已知条件３的陈述。不能作为假设。