What conditions do grass fuels exist in?

Grass fuels can exist in both green and cured conditions, which is why that choice is correct.

When grass is in a green state, it typically retains moisture, making it less flammable than cured grasses; however, once the grass dries out and becomes cured, its combustibility increases significantly. Grasslands can have a mixture of both green and cured plants at various times, particularly in transitional seasons like late spring and early fall.

The other conditions described do not fully characterize the presence of grass fuels. While grass may be found in dry weather conditions, it is not exclusive to that environment, as green grasses exist when there is sufficient moisture. Wet and humid conditions generally make grass less suitable for burning due to the increased moisture content, and the mention of only cured grass overlooks the existence of green grass, which also contributes to the fuel load. Therefore, recognizing that grass fuels can operate in both states (green and cured) is vital for understanding fire behavior and mitigation strategies.