The control account is prepared in the general ledger of a company.
A control account is a summary account that shows the total balance of a group of subsidiary accounts. For example, the accounts receivable control account summarizes the balances of all the individual customer accounts in the sales ledger. Similarly, the accounts payable control account summarizes the balances of all the individual supplier accounts in the purchases ledger.
The general ledger is the main ledger of a company that contains all of the summary accounts, including control accounts, and is used to prepare the company's financial statements. All the transactions from the other subsidiary ledgers (such as the sales and purchases ledgers) are posted to the general ledger through the control accounts.
Therefore, the correct option in this case is "general ledger," as the control account is prepared in the general ledger of a company.