
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 $x_{k+1} = x_k + 1$ for $k=1, 2, \dots, n-1$ and $x_1=2$, find $x_1 + x_2 + \dots + x_n$.
A) $\frac{n(n+1)}{2}$ 
B) $\frac{n(n+3)}{2}$ 
C) $n(n+1)$ 
D) $\frac{n(n+2)}{2}$ 
E) $\frac{n(n+5)}{2}$

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