To solve this problem, we need to choose the Venn diagram that best represents the relationship between the following classes: Stationery, Pen, and Pencil.

Step-by-step Explanation:

• Stationery: This is the broader category, which includes various writing and office supplies, such as paper, pens, pencils, erasers, etc.
• Pen: This is a type of stationery item specifically meant for writing.
• Pencil: Like a pen, this is also a type of stationery item meant for writing or drawing.

Given the above definitions, both pens and pencils are subsets of stationery. However, they are distinct from each other and do not overlap. Thus, the correct Venn diagram should show pens and pencils as separate circles within the larger circle of stationery.

Now, let's analyze the options:

• Option A: This diagram shows overlapping circles, indicating that there is some intersection among the categories, which is incorrect in this context.
• Option B: This shows three separate circles, implying no relationship, which is also incorrect.
• Option C: This suggests that one category is within another in a nested manner, but it doesn’t represent our scenario correctly.
• Option D: This option has two smaller non-overlapping circles inside a larger circle. This perfectly represents the relationship where pens and pencils are both contained within stationery but are distinct from each other.

Conclusion: Therefore, the correct answer is Option D.