Ask HN: what are considered to be succesful signup rates?

This is a quick survey. I've built a website that offers visitors a way to organize useful information for their trip. I have no user's yet, on the other hand I offer a tool and therefore there is no much need for user generated content.

What do you think is considered a logical sign up rate (the percentage from the entire visitors)? Signup is real simple and includes connecting with either Facebook or Google.

A: 1-3% B: 5-7% C: 7-15% D: 15-25%