What are common types of governors found in small engines?

The correct choice identifies common types of governors used in small engines as air vane, mechanical, and electronic, which are all widely employed to help regulate engine speed.

Air vane governors utilize a rotating air vane that moves in response to engine speed, adjusting the throttle to maintain a set speed, making them simple and effective for small engines. Mechanical governors use a system of springs and weights linked to the throttle, allowing for precise speed regulation as engine power changes. Electronic governors are becoming increasingly popular, as they utilize sensors and electronic controls to manage engine speed with high accuracy. This versatility makes them suitable for various applications, from lawn mowers to generators.

The other options include components that are either not common types of governors within this context or are not actual types of governors at all. For example, hydraulic governors are less commonly found in small engines, as most small engines typically utilize mechanical or electronic methods for speed control. Flywheel governors, while related to engine speed control by adjusting loads, are not standard in the context of small engine applications. Mentioning aliens adds an unrelated and incorrect element to the discussion. Thus, the choice correctly encompasses the prevalent types of governors in the small engine domain.