Which vapors burn with lightning rapidity upon ignition according to the provided text?

Gasoline is known for its ability to produce vapors that are highly flammable and can ignite very quickly upon contact with an ignition source. This rapid ignition is attributed to gasoline's low flash point, which is the minimum temperature at which vapors can ignite in air. The vapors of gasoline are heavier than air, allowing them to accumulate at lower levels and create a more explosive environment if an ignition source is introduced.

In contrast, while other substances such as diesel, propane, and ethanol also have flammable properties, their ignition characteristics differ. Diesel has a higher flash point and generally ignites less rapidly than gasoline. Propane, while it is flammable, typically requires a different environment for ignition due to its behavior as a gas at room temperature. Ethanol, although it can ignite quickly, does not match the speed and volatility of gasoline vapors in terms of “lightning rapidity.” Therefore, gasoline stands out as the answer in this context, given its unique properties that favor swift ignition.