The color of the eyes should always be as dark as possible, with 1A the best. It is not so much a functionality reason, since the eyes can work either light or dark, but an all important type trait. As the eye color gets lighter it softens the appearance of the gaze, diminishing the fearlessness of Rottweiler expression.
(Shapes and Placement of Eyes - Read this for the colors )
Another factor in striving to keep the eye color dark...