Answer:
B. To appear authoritative.
Explanation:
In the article "PRO/CON: Should Congress consider comprehensive climate change laws?", McClatchy-Tribune News presents two sides of the arguments about global warming especially concerning the American households. This article provides the pros and cons of greenhouse gases and their effects, along with reasonings for the presented arguments.
The PRO statement starts with the sentence <em>"In a report released this fall, the Intergovernmental Panel on Climate Change (IPCC) said that warming of the Earth's climate system is both unequivocal and unprecedented."</em> In starting the argument with the report, the author is presenting himself as authoritative, someone who knows what he is aware of and what he wants, and what he expects.
Thus, the correct answer is option B.
