Which specialized indirect vision mirror on heavy trucks is specifically designed to eliminate the blind spot directly in front of the high cab bumper (Class VI front-view mirror / 前下视镜)?

1. The front downward cross-view mirror mounted above the windshield to view pedestrians and obstacles immediately adjacent to the front bumper
2. The interior rearview mirror mounted on the center cab dome
3. The standard flat main mirror (Class II) mounted on the driver's side door
4. The aerodynamic rear fender camera used for highway cruising alignment