Before driving, where should your head be while you adjust the interior rear-view mirror?

Correct answer: In the position it will normally occupy when you drive.

Why

Set the interior rear-view mirror before moving, keeping your head in its normal driving position and showing as much of the rear window as possible. SGI gives different positions for the exterior mirrors: lean toward the left window for the left mirror and toward the centre of the car for the right mirror. The normal-head-position instruction must not be applied to all three mirrors as if their adjustment methods were identical.

Verified against Saskatchewan Driver's Handbook: A Guide to Safe Driving · Basic driving skills · p. 127