Final answer:
To import a Photoshop document into Illustrator and retain the ability for revisions and non-visible layers, the option 'Preserve layers' should be selected to maintain the original document’s layer structure.
Step-by-step explanation:
When importing a Photoshop document into Ai (Adobe Illustrator) with the intent to allow revisions and include non-visible layers, you should choose the option to Preserve layers. This option maintains the layer structure as it is in the Photoshop document, meaning that layers are not flattened or merged, and even non-visible layers are retained, making it possible to edit them later within Illustrator. This is essential for maintaining the maximum editability of your document.