Which statement about foam streams operated from elevated master streams is true?

When discussing foam streams operated from elevated master streams, it's important to understand the properties and effectiveness of different types of foam. The correct statement highlights that nonaerated foam tends to achieve a quick knock down of flames but does not provide an effective blanket over the fuel, which is essential for preventing reignition and suffocating the fire.

Nonaerated foam is designed to extinguish flames rapidly due to its fluid properties and is effective in creating a vapor suppression layer. However, it may not generate the stable, insulating foam blanket necessary to cover the surface of fuels, especially when dealing with flammable liquids. This limitation is significant because without a proper foam blanket, there's a risk of flare-ups and the potential for the fire to restart.

In contrast, the other options emphasize capabilities or restrictions that do not accurately reflect the characteristics of foam types. For instance, the assertion that all foam types create a blanket over fuel does not hold true in practice, as different formulations behave differently under specific conditions. Additionally, while aqueous film-forming foam (AFFF) is versatile, stating that only AFFF can be used excludes many effective foam agents available in firefighting. Lastly, the idea that aerated foam is less effective in knock down is misleading; aer