Here's a problem to solve: Kerry made a simple flashlight. She recorded the following statements in her lab book. Which statement is an inference?

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

- A: The wire was 35 cm long.
 
- B: The flashlight contained a battery.
 
- C: The plastic switch was better than the metal switch.
 
- D: The bulb was lit for 20 minutes before it burned out.
 