Here's a problem to solve: A bar magnet was moved quickly back and forth in a coil of copper wire. The ends of the wire were connected to a small lightbulb. Which of the following was the device created for?

Among the 4 following options, which is the correct answer?

- A: to generate an electric current
 
- B: to increase the strength of the magnet
 
- C: to heat the copper wire
 
- D: to transfer protons to the lightbulb
 