According to the United States Bureau of Reclamation (USBR) design specifications in 'Design of Small Dams' for embankment earthfill dams with heights less than $60\text{ m}$, the recommended minimum net freeboard above the top of the closed spillway control gates at maximum reservoir water level is $2.5\text{ m}$ ($8\text{ ft}$) to guard against wind wave action and overtopping. Option analysis: (A) $2\text{ m}$ to $3\text{ m}$ is a general guideline for ungated crests. (B) $2.5\text{ m}$ above top of gates is the specific USBR standard for controlled gated spillways. (C) $3\text{ m}$ is excessively high for small to medium dams. (D) Does not match the standard.