When teaching a learner to reverse into a space where visibility is limited, what should the ADI emphasise as best practice?

1. Get out and look before reversing if unsure, and maintain continuous all-round observation and control throughout the manoeuvre
2. Reverse quickly to minimise time spent in the blind area
3. Rely solely on the rear-view mirror, ignoring the door mirrors and over-the-shoulder checks
4. Ask a passer-by to reverse the vehicle instead of the learner