A vehicle’s blind zone is an area that:
Correct answer: D – Cannot be fully checked without moving your head or body
Blind zones are areas around your vehicle that are not visible from your normal driving position. Adjusting the mirrors can reduce these zones, but it does not eliminate them. Before changing lanes or moving laterally, make a full visual search by checking the mirrors and moving your head and body enough to verify that the blind zone is clear.
Source: Washington State Driver Guide — Ch. 2, § 2.12, “Your blind zones”

