Pressure has been converted to light. Force has been converted to light. Closing an electric circuit has produced light. Opening an electric circuit has produced light.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: When a button is pushed on a battery-operated clock, the time display is illuminated. What process has taken place?
Possibilities:
- Pressure has been converted to light.
- Force has been converted to light.
- Closing an electric circuit has produced light.
- Opening an electric circuit has produced light.

Closing an electric circuit has produced light.