题目内容：
请根据短文内容，回答题。Political Spins
Last week, US White House spokesman Tony Snow sent journalists digging for their dictionaries. He called recent criticism by the former President Bill Clinton "chutzpah" ( 大胆放肆).
With just. one sentence, Snow managed to make headlines, a joke and a defense of President George W. Bush. Interestingly, this is how battles are fought and won in US politics--with carefully-worded one-liners ( 一行自幕新闻 ) made for TV which often lack substance and clarity (清晰度) .
"The amount of information that candidates attempt to communicate to people is actually getting smaller and smaller," said Mark Smith, a political science professor at Cedarville University.
This has been accompanied by a changing media environment, Smith said. In 1968, the average TV or radio soundbite (演讲中的句子或短语) was 48 seconds, according to Smith. In 1996, the average soundbite had shrunk to 8 seconds. Thus, politicians wanting publicity try to make their public communication as quotable as possible.
Campaigning politicians also use 30-second TV ads and clever campaign slogans to boost their messages. Republican presidential candidate John McCain rides to campaign stops in a bus named the "Straight Talk Express". McCain hopes the name will convince voters he plans to tell people the truth--whether it's in fashion or not. Democratic presidential candidate Hillary Clinton,on the other hand, has chosen the campaign slogan "Let the conversation begin". She hopes it will help her appear open-minded and friendly.
But one-liners, TV ads and campaign slogans all have a single key ingredient: something commonly called political "spin". Brooks Jackson, a former journalist and the current director of the non-partisan (无党派的) website FactCheck. org, calls spin "just a polite word for deception ( 欺骗) "
"I do believe that very often politicians believe their own spin," said Jackson. Strong partisans suffer from a universal human tendency: They ignore the evidence that would force them into the uncomfortable position of having to change their minds and admit that they were wrong.
Which statement is NOT true of one-liners? A．They are unclear.
B．They contain a lot of information.
C．They lack substance.
D．They are carefully constructed.
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