Choice "A" is correct. When an entity uses a trust company as custodian of its marketable securities, the possibility of concealing fraud would be reduced if the trust company deals only with the person reconciling the accounts, and not with the employees responsible for maintaining investment records.
Choice "c" is incorrect. The securities should be in the entity's name, and not the trust company's.
Choice "b" is incorrect. If interest and dividend checks are mailed directly (custody of the asset) to the employee authorized to sell the securities (authorization), incompatible duties would result which may result in fraud being concealed.
Choice "d" is incorrect. Limiting access to the assets would reduce the possibility of theft, but would not reduce the possibility of concealing fraud.