The Earth.
Mercury has the planetary orbit that has the greatest inclination to both the ecliptic and the invariable plane.
The plane of Pluto's orbit is inclined 17.2° to the plane of the ecliptic.
All planets lie in the plane of their orbit, but most spin on an that is nearly (many have tilted axes of spin) perpendicular to that plane. The one exception is the planet Uranus which has its axis of spin lying very close to its orbital plane.
Pluto has an orbit that is inclined over 17 degrees relative to the plane of the ecliptic, taking it far out of this plane. This means Pluto's orbit is tilted compared to the orbits of the other planets in our solar system.
All of the other planets have an orbital path that is within six degrees of the ecliptic. The celestial object formerly known as planet Pluto had an orbit that was about 17 degrees off the plane.
I assume you mean "around the Sun". That is the Earth's orbit. The plane of this orbit is called the ecliptic.
It is called the "ecliptic plane"
No. The Earth's orbit is absolutely parallel to the plane of the ecliptic. Of course, the Earth's orbit is DEFINED as the plane of the ecliptic, so this should be no surprise. All of the other planetary orbits are tilted to the plane of the ecliptic, but not by a whole lot. The Moon's orbit, for example, is tilted about 5 degrees to the ecliptic. The axis of the Earth's spin, however, IS tilted by 23.5 degrees to the plane of the ecliptic.
The 'ecliptic' plane is the plane that contains the Sun and the Earth's orbit around it.
The Earth orbits in the plane of the ecliptic in an ellipsoidal orbit that is nearly circular. Comets orbits are highly elliptical and mostly out of the plane of the ecliptic.
That's the "ecliptic plane".
The planets don't all orbit the Sun in EXACTLY the same plane - there are small variations. The plane where Earth orbits is called the Ecliptic; other planets orbit fairly close to that same plane.