
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 quadrilateral has vertices $P(c,d)$, $Q(d,c)$, $R(-c,-d)$, and $S(-d,-c)$, where $c$ and $d$ are positive integers with $c > d > 0$. The area of quadrilateral $PQRS$ is $18$. What is $c+d$?
**A)** 5
**B)** 7
**C)** 9
**D)** 10
**E)** 12

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