Which of the following is one way a secured creditor can control a deposit account?

A secured creditor can control a deposit account by having their name added to the account. This can be achieved through a security agreement that grants the secured party an interest in the deposit account. By being named on the account, the creditor can exert control over it and enforce their security interest, which is crucial under the UCC (Uniform Commercial Code) provisions governing secured transactions.

The other options do not accurately represent how a secured creditor can gain control over a deposit account. A loan agreement is often necessary for establishing a relationship between the debtor and creditor, but it does not in itself provide control over the deposit account. Being an owner of the bank is irrelevant as it does not provide the creditor with any authority over a debtor’s personal account. Regularly withdrawing money does not denote control; in fact, it could undermine the creditor's interest in the account. Thus, the most effective method for a secured creditor to establish control is indeed by adding their name to the deposit account.