Final answer:
The optional step during the closing process is step 3) An end-of-period spreadsheet is prepared.
Step-by-step explanation:
The optional step during the closing process is step 3) An end-of-period spreadsheet is prepared. This step involves preparing a spreadsheet that summarizes the financial information for the period, including the adjusted balances of accounts.
The other steps are essential in the closing process. Step 1) involves preparing a post-closing trial balance to ensure that all accounts have been properly closed. Step 2) involves journalizing and posting adjusting entries to update the account balances. And step 4) involves preparing an unadjusted trial balance to ensure the accuracy of the accounting records before adjustments are made.