The best medium for a guide to U.S. national parks is television, as it effectively combines visuals and narratives that can inspire viewers. While other mediums like print and email offer detailed information, they lack the engaging nature of visual storytelling. Television has the potential to enhance the audience's desire to explore the beauty of national parks. ;
The best medium to showcase a guide to U.S. national parks is television, due to its ability to engage audiences with stunning visuals and storytelling. While other options like radio, email, and print have their merits, television stands out by effectively inspiring viewers to visit these parks. Thus, the chosen option is A. Television.
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