Which of these choices is / are example(s) of a plasma?
All of these
The plasma state consists of super energetic and super excited particles. These particles are in the form of ionised gases.
Aurora Borealis is a phenomenon, where the particles in atmosphere get excited due to radiation from the sun and get ionised.
The fluorescent tube and neon sign bulbs also consist of plasma. Inside a neon sign bulb, there is neon gas and inside a fluorescent tube, there is helium gas or some other gas.