Final answer:
The Inventory account is not used in the closing process of a periodic inventory system; it is a permanent account and carries its balance into the next period.
Step-by-step explanation:
The account that is not used in the closing process for a periodic inventory system among the options listed is Inventory. The closing process involves transferring temporary account balances to permanent accounts at the end of an accounting period. Temporary accounts include revenue and expense accounts such as Sales Revenue and Cost of Goods Sold, which are closed to the Income Summary account. The Accounts Payable account is also not closed because it is a permanent or real account that carries its ending balance into the next accounting period.