The opening line that is not effective is: C.) "Once upon a time, there were two friends who did something cool, and I will tell you all about it."
This opening line is less effective because it is vague and lacks the engaging and intriguing elements found in the other options.
It doesn't provide any specific details about the characters, the situation, or the dragon, making it less compelling to the reader.
Effective narrative openings usually grab the reader's attention with vivid imagery, interesting dialogue, or a unique setting, and option C falls short in creating that initial curiosity.
Options A, B, and D offer more vivid and engaging starting points for the narrative, setting the stage for the reader to become immersed in the story about two friends raising a friendly dragon.