
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 rectangle has dimensions $4 \times 5$. A semicircle with a diameter of $2$ is removed from one end of the rectangle. Find the whole number closest to the area of the remaining shaded region.
A) 16
B) 17
C) 18
D) 19
E) 20

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