
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 factory produces four different types of products, labeled as A, B, C, and D, with production quantities of 100, 200, 300, and 400 units respectively. To inspect the quality of the products, a stratified sampling method is used to select 50 units for inspection. The number of units that should be selected from type D products is ______.

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