
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
Given points $P_1, P_2, \cdots, P_9$ on a straight line, in the order stated (not necessarily evenly spaced). Let $P$ be an arbitrarily selected point on the line and let $s$ be the sum of the undirected lengths $PP_1, PP_2, \cdots, PP_9$. Then $s$ is smallest if and only if the point $P$ is:
A) $P_1$
B) $P_2$
C) $P_4$
D) $P_5$
E) $P_9$

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