If `A sub B`, then the illustration of `A - B` in a Venn diagram is

Options

A.
B.
C.
D. None of these

Explanation

To solve the problem of illustrating \( A - B \) in a Venn diagram when \( A \) is a subset of \( B \), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- First, we need to understand what it means for \( A \) to be a subset of \( B \). This means that every element in set \( A \) is also an element of set \( B \).

2. **Defining the Sets**:
- Let's denote the universal set as \( U \).
- Set \( B \) will contain all the elements of set \( A \) and possibly more elements.

3. **Drawing the Venn Diagram**:
- Draw a rectangle to represent the universal set \( U \).
- Inside this rectangle, draw a circle for set \( B \).
- Inside the circle for \( B \), draw another circle for set \( A \) such that the entire circle of \( A \) is within the circle of \( B \).

4. **Identifying \( A - B \)**:
- The operation \( A - B \) represents the elements that are in \( A \) but not in \( B \).
- Since \( A \) is a subset of \( B \), there are no elements in \( A \) that are not in \( B \).

5. **Conclusion**:
- Therefore, \( A - B \) is an empty set, denoted as \( \emptyset \) or \( \phi \).
- In the Venn diagram, this means that there is no shaded area representing \( A - B \) because there are no elements to illustrate.

6. **Final Answer**:
- The illustration of \( A - B \) in a Venn diagram is an empty area, indicating that \( A - B = \emptyset \).