Explanation
Unmanned Aerial Vehicles (UAVs), commonly known as drones, are aircraft that operate without onboard human pilots — either remotely controlled or autonomously via onboard computers. UAVs are broadly classified into two categories: fixed-wing UAVs and rotary-wing UAVs (multicopters).
Statement I is incorrect. Not all UAVs are capable of vertical landing. Fixed-wing drones use rigid wings and a motor-driven propeller to cover long distances at high speeds. Unlike rotary-wing drones, they cannot perform vertical takeoff or landing (VTOL) and require a runway or a recovery net to land.
Statement II is incorrect. Automated hovering is a feature exclusive to rotary-wing drones such as quadcopters. Traditional fixed-wing UAVs cannot hover — they must maintain forward motion to generate lift, just like conventional aircraft.
Statement III is incorrect. While small UAVs like consumer quadcopters do run on batteries, many UAV categories cannot rely solely on battery power. High-endurance military UAVs such as the Predator and RQ-4 Global Hawk use fuel-based propulsion systems because the energy density of batteries is significantly lower than that of conventional fuel, making batteries insufficient for long-range or extended-duration missions.
Since all three statements are incorrect, the answer is None.