The correct answer is answer A ("Search for an exact phrase").
Google offers a few filters and many shortcuts or commands that you can apply in your searches to optimize efficiency. A very common and useful one is searching for an exact phrase.
The method is very simple: you think of an entire phrase and put it in-between quotation marks (for example "how to use google filters"). This will only show results from pages where this whole phrase is included just the way you wrote it.
The inclusion of reputable sources and specific facts would best strengthen the author's main argument because it would offer factual proof instead of just the author's opinion on the matter.
