The production workspace is on a Standard subscription which does not include sandbox environments is correct.

This is because the Standard subscription which does not include sandbox environments does not include sandbox support. The subscription tier determines which features are available and a Standard subscription commonly excludes sandbox environments so administrators must upgrade to a plan that includes sandboxes before provisioning one.

A sandbox is already linked to the production workspace is incorrect because the scenario describes an inability to provision a sandbox due to plan limitations rather than an existing linked sandbox. If a sandbox were already linked the administrator would normally see that existing relationship or a distinct message stating only one sandbox is allowed.

The administrator does not have the necessary organization permissions to create a sandbox is incorrect because the question specifies Marco is an organization administrator. An organization administrator typically has the required permissions so the limitation is more likely caused by the subscription level.

Paid marketplace apps on the production workspace are blocking sandbox creation is incorrect because paid marketplace apps generally do not prevent creating a sandbox. Feature availability is controlled by the subscription or plan and not by installed marketplace applications.

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