
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Evaluate the sum $1-2-3+4+5-6-7+8+9-10-11+12+13-\cdots+1996+1997-1998-1999+2000$.
A) -5
B) 0
C) 5
D) 10
E) -10

Present the answer in LaTex format: \boxed{Your answer}
user