The correct answer is D) Drift lead with the line leading perpendicular to the centerline. A drift lead with the line leading perpendicular to the centerline provides little or no indication that a vessel is dragging anchor. This is because the drift lead will indicate the vessel's drift regardless of whether the anchor is holding or not. The other options, such as changing bearings to distant fixed objects (A) or increasing radar range (B), would indicate that the vessel is moving and potentially dragging anchor. Vibrations felt on the anchor cable (C) may provide some indication, but a drift lead perpendicular to the centerline is a more direct and reliable method for determining if the anchor is holding.