When does an item disappear from view ?

Let’s say I have a single item for sale.

The product is set to ‘not show’ out of stocks.



2 buyers spot the item.



At what point will the item disappear from view:

A. When one of the shoppers puts it in his/her cart.

B. When one of the shoppers goes to checkout.

C. When one of the shoppers completes checkout.



??

I"m assuming the answer is C because the item is truly not out of stock untill the checkout process is complete.