
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 the sets of consecutive integers starting from $\{3\}$, $\{4, 5\}$, $\{6, 7, 8\}$, continuing such that each subsequent set starts one more than the last element of the previous set, and each set contains one more element than the preceding one. Let \( S_n \) represent the sum of the elements in the nth set. Calculate \( S_{15} \).
A) 1620
B) 1725
C) 1825
D) 1925

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