
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
A rectangular playground is to be fenced on three sides, using a 150 meter rock wall as the fourth side. Fence posts are to be placed every 10 meters along the fence, including at the corners where the fence meets the rock wall. If the playground measures 50 m by 100 m, what is the minimum number of fence posts needed?
A) 19
B) 20
C) 21
D) 22
E) 23

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