If a choice selection is linked to a Shopify variant, the inventory of that variant will be appropriately reduced after the purchase process has been completed.
If a selection choice doesn't have any Shopify variants linked to it, inventory will not be reduced, and that selection's information will simply be listed in the cart.
As of February 19th, 2021, Product Builder is unavailable for new installations. If you are currently using Product Builder, you will be able to continue using the app as your account will now be grandfathered.
Please visit Change Inventory Management Settings for more information on how to adjust these settings within Product Builder.