请问一道逻辑题

To prevent some conflicts of interest,
Congress could prohibit high-level government officials

from accepting positions as lobbyists for
three years after such officials leave government service. One such official
concluded, however, that such a prohibition would be unfortunate because it
would prevent high-level government officials from earning a livelihood for
three years.

The official’s conclusion logically depends
on which of the following assumptions?

B.
Lobbyists are typically people who have previously been high-level government
officials.

D.
High-level government officials who leave government service are capable of
earning a livelihood only as lobbyists.

答案是d但是我觉得b更好啊。因为文章最后一句只是说会妨碍官员谋生，并没有官员就一定找不到工作啊。而d说的太绝对了。

我猜原因是否是b给说反了，应该是高官一般都会做说客。

我觉得d把only去掉我就选了。

D is right. 正因为lobbyist是唯一陌生手段，所以才 would be unfortunate because it would prevent high-level government officials from earning a livelihood for three years.

evidence + assumption = conclusion 所以用B并不能推出livelihood... （而且B看上去就无关，应先排除）

 "prevent high-level government officials from earning a livelihood"就应该理解为“无法谋生“吧。所以D并不绝对，而正好是原文推理过程中隐含的这个“绝对的"前提条件.