Randox Industries has the following investment policy statement: "In order to achieve the safety and liquidity necessary in the investment of excess cash balances, the CFO or his designee may invest excess cash balances in 30 - day U. S. Treasury bills, or in bankers acceptances with maturities of less than 31 days or 30 - day certificates of deposit, where the credit rating of the issuing bank is A + or higher. " This policy statement is.（）
A. appropriate because these are all safe, liquid securities.
B. inappropriate because it is too restrictive.
C. inappropriate because both banker’s acceptances and certificates of deposit are illiquid.