
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
If the sum of the first three terms of an arithmetic sequence is 34, the sum of the last three terms is 146, and the sum of all terms is 390, then this sequence has (  )  
A  13 terms    B  12 terms        C 11 terms              D 10 terms

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