Which instruments can be classified as money market instruments?

Treasury bills, which are short-term debt securities issued by the U.S. government, fall under the classification of money market instruments. Money market instruments are typically characterized by their short maturities, high liquidity, and low risk. Treasury bills are issued with maturities ranging from a few days to a year, making them a quintessential example.

American depository receipts represent shares of foreign companies traded on U.S. exchanges, and are not classified as money market instruments due to their longer-term nature and association with equity rather than short-term debt. Bankers' acceptances and commercial paper are also indeed money market instruments, as they are used in short-term financing and have high liquidity. However, since the question asked specifically about which of the provided options classifies as money market instruments, Treasury bills stand out as a primary example of these instruments, thereby serving as the most straightforward and common answer.