Which of the following represents a type of somatogyral illusion?

A somatogyral illusion occurs when the vestibular system misinterprets the position or movement of the body, particularly regarding linear and rotational movement. The leans specifically refer to a type of somatogyral illusion where a pilot experiences a sensation of banking in one direction, even when the aircraft is level. This can happen when a pilot is exposed to prolonged uncoordinated flight, causing a misperception of the aircraft's true attitude relative to the horizon.

The other options do not represent somatogyral illusions. A false horizon involves misinterpretation of the natural horizon due to visual cues that might mislead a pilot, such as an uneven terrain. Autokinesis refers to the perception of motion of a stationary light in darkness, which occurs because of the eye's physiological responses and is not related to the vestibular system's interpretation of motion. Spatial disorientation is a broader term that encompasses various forms of confusion regarding one's orientation in space, but it is not limited to the specific sensations found in somatogyral illusions. Therefore, the leans are uniquely categorized as a type of somatogyral illusion.