Correct Option (D)
None
Explanation
The statements provided are not universally applicable to all types of Unmanned Aerial Vehicles (UAVs), which constitute a diverse category of aircraft with varied designs, propulsion systems, and operational capabilities.
Statement 1: All types of UAVs can do vertical landing.
This statement is incorrect. Vertical landing is a capability primarily associated with multirotor UAVs (e.g., quadcopters) and hybrid Vertical Take-Off and Landing (VTOL) models. Fixed-wing UAVs, which rely on aerodynamic lift generated by forward motion, typically require a runway for landing or employ recovery systems such as nets or parachutes. They cannot perform vertical landing.
Statement 2: All types of UAVs can do automated hovering.
This statement is incorrect. Automated hovering, the ability to remain stationary in the air without constant pilot input, is a characteristic feature of multirotor UAVs. Fixed-wing UAVs, similar to conventional aircraft, require continuous forward motion to generate lift and maintain flight. They are inherently incapable of hovering.
Statement 3: All types of UAVs can use battery only as a source of power supply.
This statement is incorrect. The power supply for UAVs varies significantly based on their size, mission, and endurance requirements. While smaller consumer drones often rely on batteries, larger and more complex UAVs, especially those used for military or long-endurance applications, frequently utilize internal combustion engines (powered by petrol, diesel, or aviation fuel) or hybrid propulsion systems. Batteries alone often lack the energy density required for extended flight times or heavy payloads in such larger systems.
Incorrect Options
Options (1) Only one, (2) Only two, and (3) All the three are incorrect because, as detailed above, none of the three statements regarding UAV capabilities and power sources are universally applicable across all types of Unmanned Aerial Vehicles. The inherent diversity in UAV design, propulsion, and operational roles means that features like vertical landing, automated hovering, and battery-only power supply are specific to certain categories rather than being universal characteristics.