Experiments have shown that a transitional fire attack slowed the growth of a fire by:

The effectiveness of a transitional fire attack is primarily attributed to its ability to cool large volumes of gases and fuels below their ignition temperature. By introducing water in its aerosol or fog form during the attack, firefighters can reduce the overall temperature within the fire environment. This cooling effect can suppress the heat necessary for combustion, which in turn helps to slow down the fire's growth.

Moreover, this technique minimizes the risk of flashover, a sudden and intense fire spread, by addressing the temperature of the smoke and heated gases directly above the fire. This is particularly critical in high-stress environments where rapid temperature shifts can provide more control and enhance safety for both the firefighters and any potential victims.

The other choices, while they address important aspects of fire dynamics, do not adequately capture the precise mechanism through which a transitional fire attack works to slow down fire growth. Limiting air may affect combustion but isn't the primary focus of a transitional attack, soaking combustible materials tends to apply to a later stage of firefighting, and pushing smoke and gases towards ventilation openings does not minimize the fire's intensity effectively in terms of cooling.