
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
Square corners, each 8 units on a side, are removed from a 40 unit by 60 unit rectangular sheet of cardboard. The sides are then folded to form an open box. The surface area, in square units, of the interior of the box needs to be calculated.
A) 2000 square units
B) 2144 square units
C) 2200 square units
D) 2400 square units
E) 2560 square units

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