Which factor is likely to be affected if there is too much weight aft of the CG?

If there is too much weight positioned aft of the center of gravity (CG), it greatly compromises control stability. The center of gravity is the point at which the total weight of the aircraft is considered to act, and it plays a critical role in determining how an aircraft will behave in flight. When the CG shifts too far aft, it can lead to decreased longitudinal stability, making the aircraft more difficult to control, particularly during maneuvers or when encountering turbulence.

Aircraft with a CG that is too far rearward may experience a tendency to pitch up, and it might also require more control input to maintain level flight, leading to a feeling of sluggishness or reduced responsiveness. Additionally, this condition can increase the risk of stalling, as it can affect the angle of attack at which the aircraft will stall, making it harder to recover from such situations.

In contrast, the other options do not directly relate to the operational and safety implications of having weight positioned too far aft of the CG. Engine efficiency, aircraft color, and stall characteristics are not significantly impacted by CG placement in the same critical way that control stability is.