Which of These Controls Would Be the Most Effective in Assuring

Which of these controls would be the most effective in assuring that the proper custody of assets in the investing cycle is maintained?

A) The purchase and sale of investments are executed on the specific authorization of the board of directors.
B) The recorded balances in the investment subsidiary ledger are periodically compared with the contents of the safety deposit box by independent personnel.
C) Direct access to securities in the safety deposit box is limited to only one corporate officer.
D) Personnel who post investment transactions to the general ledger are not permitted to update the investment subsidiary ledger.