Concept:An advertising display that uses electric current in gas-filled bulbs is called a neon sign.
Explanation:Neon signs consist of glass tubes filled with neon or other gases.
When an electric current passes through these tubes, it excites the gas molecules.
The excited gas then emits bright, coloured light.
This makes neon signs highly visible, especially at night.
They are widely used on storefronts and buildings for outdoor advertising.
This feature directly matches the description in the question.
Answer:C. neon signs