I only need help with the italicized part. Thanks

Problem 75

Computer World, Inc., desires to borrow money from Investment Bank of America, which will grant it a revolving line of credit, secured in part by the bank account that Computer World maintains at Last National Bank. You are the attorney for Investment Bank of America. Advise the bank how it can perfect its security interest in this bank account and which of the methods of control specified in 9-104 would be the safest form of security.

If Computer World later borrows money from Last National Bank and grants the bank a security interest in the account carried there, would Last National have priority over your client?

Problem 75 SECURED TRANSACTION MASTER OUTLINE-Swanson_SecuredTrans_Spring_2014 (1): Advise the bank how it can perfect its security interest in this bank account and which of the methods of control specified in 9-104 would be the safest form of security. I know the three methods per 9-104. I am unsure how to determine which option is best for Investment Bank of America, my client, secured party?