user
I am here but yet am not  standing in your doorway  i am always here for you  what am i?
A: folding door
B: room
C: venue
D: your friend
E: lego set
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

D

<|end_of_solution|>