
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 an arithmetic sequence where the first term is $4k^2 - k + 1$ and each term increases by 2. If you need to calculate the sum of the first $3k$ terms of this sequence, how can you express it?
A) $12k^3 + 5k^2$
B) $12k^3 + 6k^2$
C) $12k^3 + 6k^3$
D) $15k^3 + 9k^2$

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