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.
