user
I am one small little piece of paper, yet sometimes hold lots of value.  I am all you need to get in to big events, but will cost you.  I am an important part of travel.  And if lost, you're not coming.  What am I?
A: credit
B: take
C: highlighting
D: plane
E: ticket
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

E

<|end_of_solution|>