user
I am a lightbulb.  Someone flicks the switch.   I usually turn on, but i didn't this time.   The person checks the outlet, and i am plugged in all the way.  Why didn't i turn on. 
A: dimness
B: back off
C: degree
D: i burned out
E: ignition
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

D

<|end_of_solution|>