Which of the following is a requirement for vessels over 26 feet?

The requirement for vessels over 26 feet to have discharge of oil prohibited placards displayed is essential for compliance with the regulations set forth under the Clean Water Act and the Oil Pollution Act. These placards serve to inform crew and passengers about the legal prohibitions regarding the discharge of oil into navigable waters, helping to protect the environment and marine life.

While the other safety measures listed, such as life jackets, emergency flares, and two-way radios, are also important for vessel safety and operation, they do not specifically pertain to the regulatory requirement tied to preventing oil pollution. Therefore, the display of oil discharge prohibition placards is a distinct legal necessity for this size of vessel, emphasizing the responsibility of vessel operators to maintain environmental integrity while on the water.