Final answer:
The mirror setting for a vehicle should include a view of the side and the rear of the vehicle. Side-view mirrors are typically convex to provide a wider field of vision. At least two mirrors are needed to see the back of one's head, and the size of the mirror is independent of the distance from it.
Step-by-step explanation:
When adjusting the mirror, if the setting is for a standard side-view or rear-view mirror on a vehicle, the correct view typically includes some of the side of the vehicle (option 1) to ensure proper spatial orientation and to reduce blind spots. Additionally, the mirror setting should allow the driver to see part of the rear of the vehicle (option 2) and the area behind the vehicle to monitor traffic and safety conditions. Mirrors are not designed to show the front of the vehicle (option 3) or the driver's face (option 4) except for the purpose of personal grooming or adjustment in the case of a vanity mirror, which is typically located inside the vehicle above the dashboard.
In answering another related question, for a standard side-view mirror on a car that has the statement 'Objects in mirror are closer than they appear,' the correct answer would be that the mirror is convex. Mirrors on the side of the car often have this property to provide a wider field of view, although it distorts distance perception. To confirm the shape of the mirror experimentally, one could look at how straight lines are reflected in the mirror: a convex mirror will make them appear curved outwards.
To see the back of your head using mirrors, you would need at least two mirrors positioned at an angle. This enables you to see the reflection of the back of your head from one mirror to the other. The size of the mirror does not matter, as it's the angles that are important. However, for full-body visibility, a full-length mirror that is at least half your size and positioned so that the top edge is at the level of your eyes would suffice, as per Figure 25.47.