In which of the following scenarios would a two-stroke engine be preferable?

A two-stroke engine is preferable in scenarios involving portable power tools due to its lightweight design, compact size, and simplicity of construction. These engines operate on a two-stroke cycle, which allows for a power stroke with every revolution of the crankshaft. This design leads to higher power-to-weight ratios compared to four-stroke engines, making them ideal for applications where portability and ease of use are key factors.

Additionally, two-stroke engines can be designed to use a mixture of fuel and oil, simplifying fuel supply requirements and enabling easier maintenance in portable equipment. This is particularly advantageous for tools like chainsaws, leaf blowers, and small generators, where frequent movement and maneuverability are essential.

In contrast, long-distance highway travel typically requires engines that are designed for fuel efficiency and longevity, which is a strength of four-stroke engines. Heavy-duty construction equipment often benefits from the torque and durability provided by larger, robust engines as well. Finally, large buses require engines that prioritize fuel economy, emissions control, and longer operating intervals, which are characteristics found in advanced four-stroke systems.