
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
Calculate $k$ such that $3^{1999}-3^{1998}-3^{1997}+3^{1996} = k \cdot 3^{1996}$.
A) 14  
B) 15  
C) 16  
D) 17  
E) 18

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