Surface tension will be insufficient in which type of fire?

Surface tension plays a critical role in how certain fuels behave during combustion. In gas-driven fires, the combustion process is primarily reliant on the fuel gas mixing with oxygen in the air, so surface tension is not a significant factor. Similarly, heat-driven fires are driven by the transfer of heat rather than by the properties of a liquid fuel and, therefore, surface tension does not limit combustion in these scenarios either.

However, in a wind-driven fire, the influence of wind can disrupt the surface tension effects, allowing for more severe fire behavior. Wind increases the supply of oxygen to the fire and can spread the flames more rapidly, making the fire behave more aggressively than it would without wind.

In contrast, liquid-driven fires primarily involve liquids, which are explicitly affected by surface tension. In these fires, surface tension can play a vital role in how the fuel spreads and ignites, which is why surface tension is particularly important to consider in those cases.

Thus, the correct response indicates that surface tension is not a limiting factor in the context where wind affects the fire's behavior significantly, making wind-driven fires the correct choice where surface tension is insufficient.