Concept:A device changes energy from one form to another. We need the device whose input is electrical energy and whose useful output is light.
Solution:A fluorescent tube uses electrical energy to excite mercury vapour inside the tube.
This produces ultraviolet light, which makes the phosphor coating on the tube glow with visible light.
So it changes electrical energy into light energy.
An electric bell changes electrical energy mainly into sound energy.
A radio changes electrical energy into sound energy through its loudspeaker.
A lantern (kerosene lantern) changes the chemical energy of the fuel into light and heat, not electrical energy into light.
Answer:Option B (Fluorescent tube)