题目选项分析

Public health expert: Increasing the urgency of a public health message may be counterproductive. In addition to irritating the majority who already behave responsibly, it may undermine all government pronouncements on health by convincing people that such messages are overly cautious. And there is no reason to believe that those who ignore measured voices will listen to shouting.

The two sections in boldface play which of the following roles in the public health expert's argument?

【选项】The first is the argument's main conclusion; the second supports that conclusion and is itself a conclusion for which support is provided.