
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
Consider a geometric sequence where the first term is $k^3$ and the common ratio is $2$. Find the sum of the first $k$ terms of this sequence.
**A)** $k^3 + 2^k$  
**B)** $k^2 + 2^k$  
**C)** $k^3 (2^k - 1)$  
**D)** $2k^3 + k^2$

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