
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
Let $n$ be a positive integer. If the equation $3x + 3y + z = n$ has 15 solutions in positive integers $x$, $y$, and $z$, then $n$ could be which of the following?
A) 18
B) 19
C) 20
D) 21
E) 22

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