Greased Lightning-10 aircraft technology

Greased Lightning-10 (GL-10) is an experimental electric aircraft that was tested by NASA. It is a prototype of an electric vertical takeoff and landing (eVTOL) aircraft designed to demonstrate advanced aeronautical technologies for quieter, more energy-efficient aircraft. NASA conducted flight tests of this vehicle to explore future possibilities in aviation technology. Option b refers to solar-powered aircraft (like Solar Impulse), which is different from GL-10. Option c and d refer to space technology and rockets, not aircraft. GL-10 was specifically mentioned in news reports related to NASA's experimental aviation projects in 2015-2016.