Which type of engine is characterized by igniting compressed fuel using a spark?

The correct answer is based on the defining characteristics of various engine types. A gasoline engine ignites fuel by using a spark plug, making it dependent on the spark for combustion. This ignition method effectively allows the air-fuel mixture to ignite at the precise moment for optimal performance.

In contrast, a diesel engine relies on compression ignition, where air is compressed to such a high degree that the temperature rises sufficiently to ignite the fuel when it is injected. This fundamental difference separates gasoline engines from diesel engines.

While four-stroke and two-stroke refer to the cycles of engine operation, they do not specifically indicate the ignition method. Both of these types can be based on gasoline or diesel fuel. The significant detail here is that the spark ignition is a hallmark of gasoline engines, confirming why the selection of this answer is appropriate.