Final answer:
Option (A), The toilet featured in the video has an eco-friendly design as it transforms human waste into clean water and plant growth. It's unique because it utilizes natural wetland processes for filtration.
Step-by-step explanation:
The unique feature of the toilet shown to Lee Blaney in the Science Friday video was that it converted human waste into cattails and clean water. Although the options provided include a built-in bidet, being self-cleaning, using minimal water, and having advanced flushing technology, the video highlighted its eco-friendly approach by emphasizing how wetlands filter water. The inventor of the toilet-boat, Adam Katzman, designed this system to leverage natural processes to treat human waste, which is not only innovative but also environmentally beneficial.