What does the Idaho state flag feature?

The Idaho state flag prominently features the state seal set against a blue background. The seal includes imagery representative of the state's natural resources and history, such as an elk and a woman symbolizing liberty. The blue background symbolizes the skies and water resources of Idaho. The design of the flag is meant to convey Idaho's identity and values, making the combination of the state seal and blue background the defining elements of the flag.

While the other options suggest different symbols or colors that might represent aspects of Idaho, they do not accurately depict the official flag as established. The state motto being in white letters and the presence of a mountain or river, or a golden eagle and sun, do not align with the flag's actual design. Therefore, the correct representation of the Idaho state flag is indeed the state seal set against a blue background.