OPT:
A). sunlight.
B). energy.
C). a light source.
D). batteries.
E). circuits.
F). energy usage.
G). heat energy.
H). power.
Given those answer options, answer the question: Fact 1: Aflashlight requires a source of electricity to produce light. Fact 2: Electricity flows when a battery is connected to an object like a watch, toy, or flashlight. Given the two facts above, what do flashlights require to produce light?
A:
D).