A regular incandescent bulb is 7% efficient. Which of the following statements best explains this statement?
A.
For every 100 units of electrical energy that enter a light bulb, 7 units are changed into light energy.
B. Every hour that a light bulb is on it uses 7 kW of electric energy.
C. 7 % of the electrical energy that reaches a light bulb is wasted as heat.
D. 7 % of the electrical energy that reaches a light bulb goes right through without being used.