If you see a lock icon and a password prompt when you try to start up a Mac with Apple silicon to recoveryOS, the most likely reason is that your Mac is enrolled in an MDM solution and has a recoveryOS password set by the administrator. This password prevents unauthorized access to the recovery environment and the startup options screen, where you can change the security policy, erase the internal storage, or reinstall macOS. You need to enter the correct password to proceed to recoveryOS. If you don't know the password, you should contact your administrator or the organization that manages your Mac. The other options are not the most likely reasons for this screen to appear, as they have different effects or symptoms.
* A FileVault password is used to unlock the encrypted startup volume, not the recoveryOS. If your Mac has a FileVault password set, you will see a different screen that asks you to enter the password or the recovery key to unlock the disk. You can still access the recoveryOS without entering the FileVault password by holding down the power button until you see the startup options screen.
* A security policy that disallows access to recoveryOS is not possible on a Mac with Apple silicon. The security policy only affects the ability to boot from external media or run non-Apple operating systems.
You can always access the recoveryOS by holding down the power button until you see the startup options screen, unless there is a recoveryOS password set by an MDM solution.
* A Startup Utility password is not a feature on a Mac with Apple silicon. The Startup Utility is an app that lets you select a startup disk on a Mac with Intel processor. On a Mac with Apple silicon, you can select a startup disk from the startup options screen, which may require a recoveryOS password if your Mac is enrolled in an MDM solution. References:
* Apple Device Support Exam Prep Guide, page 8
* Use macOS Recovery on a Mac with Apple silicon
* Revive or restore a Mac with Apple silicon using Apple Configurator
* How to Enter macOS Recovery Mode on Apple Silicon Macs
* How to Enter macOS Recovery on an Apple Silicon Mac - MUO
* Any way to block Safe Mode on a Macbook w/ an M1 chip?

To start Apple Diagnostics on a Mac, shut it down, then press the power button and immediately hold Command-D until diagnostics begin (progress bar appears). This works on Intel and Apple silicon Macs (post-startup options on silicon).
* Option A: Option-D starts Internet Diagnostics (older Macs), not standard Diagnostics.
* Option B: Command-Option-D isn't a valid combo.
* Option D: Shift-D isn't used.
References: Apple Support - " Use Apple Diagnostics on your Mac " (support.apple.com/HT202731).