Final answer:
Andrew Keen's main claim is that the Internet is a double-edged sword with both benefits and drawbacks.
Step-by-step explanation:
Andrew Keen's main claim in the debate is B. The Internet is a double-edged sword with both benefits and drawbacks. Keen argues that while the internet offers numerous advantages, such as easy access to information and global connectivity, it also brings negative consequences like the spread of misinformation, online harassment, and the erosion of privacy. He believes that society must find ways to mitigate these effects and ensure a more balanced use of the internet.