The planet that matches the provided characteristics is Saturn.
- No solid surface: Saturn is a gas giant.
- Hot liquid deep inside: It has a hot, liquid interior.
- A rocky core at the center: Saturn has a core that is believed to be made of rock and metal.
- Rings made of small particles and dust: Saturn is well-known for its prominent ring system.
- 67 known moons: Saturn has a significant number of moons, including Titan, which is one of the largest moons in the solar system.
Therefore, the correct response is Saturn.