Indicate the true statements concerning determining the occlusal plane in edentulous patients:

1) technically, the orientation of the occlusal plane is registered on the lower occlusion rim;
2) orientation of occlusal plane is registered on the upper occlusion rim, and then it is transferred to the lower occlusal rim;
3) occlusal plane runs along the contact surface of the upper and lower occlusion rims;
4) the position of the plane is related to the facial extraoral auxiliary lines: Camper’s line, Frankfort line, inter-pupillary line;
5) in the anterior region, the upper occlusion rim curvature should support the lip and should be parallel to the inter-pupillary line and be visible at about 1.5-2 mm at slight mouth opening (when lips are at rest);
6) in the anterior region, the occlusion rim should be slightly visible from under the upper lip and should be parallel to the Camper’s line;
7) in the posterior region, the occlusal rim should be parallel to the Camper’s ala-tragal line;
8) in the posterior region, the occlusal rim should be parallel to the Frankfort plane.
The correct answer is: