b. They orbit around the Sun in a counterclockwise direction, when viewed from above the ecliptic plane.
Explanation:
All the objects of the solar system revolve around the Sun in a counterclockwise direction. The comet coming from the Oort's cloud will also follow the same kind of orbit. That is why it can't be a property to distinguish an Oort's cloud comet.
All other properties are correct to identify an Oort's cloud comet as the Oort's cloud is a considered a spherical cloud just outside the Solar system.
