A,D.

These are 2 complete solutions on their own. Not a step by step by step.
1) Add the rule and enable it.
2) Add the rule, set the rule to overwrite existing rules, and enable it.

"Set-MpPreference will always overwrite the existing set of rules. If you want to add to the existing set, use Add-MpPreference instead."
https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/enable-attack-surface-reduction?view=o365-worldwide#powershell

The command does not need to mention anything about block because the GUID references a Rule with already set actions.

Configuration Manager name: Block Office application from creating child processes
GUID: d4f940ab-401b-4efc-aadc-ad5f3c50688a
https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/attack-surface-reduction-rules-reference?source=recommendations&view=o365-worldwide#block-all-office-applications-from-creating-child-processes