Answer:
An online article from The Washington Post.
Step-by-step explanation:
This is the source which is most likely to provide reliable information about climate change. This is because The Washington Post is a reliable publication that takes great care of reporting facts in an accurate way. An online article from Nancy's blog is likely to be biased, as it expresses a personal opinion. A student essay and the comments on a library website are not written by experts, which means they can contain inaccurate information.