
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 playing field is to be fenced on three sides using one existing $150$ meter stone wall as the fourth side. Fence posts are to be placed every $15$ meters along the $150$ meter side, and every $10$ meters on the shorter sides. What is the fewest number of posts required if the playing field measures $50$ m by $150$ m, and the posts at the connections between sides need not be doubled?
A) 18
B) 19
C) 20
D) 21
E) 22

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