
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
Determine the number of digits in the sum of the following three whole numbers:
\[\begin{tabular}[t]{cccc} 6 & 5 & 4 & 3 \\ & C & 7 & 5 \\ & D & 6 \\ \hline  \end{tabular}\]
where $C$ and $D$ are nonzero digits.
A) 3
B) 4
C) 5
D) 6

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