user
Guides travelers, never moves, Always turning, never looks, Always shining, never burns, Looks on blue fields with each of its turns.  What is it?
A: pan
B: houses
C: blinker
D: lighthouse compass or buoy
E: tool
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

D

<|end_of_solution|>