Bird flue affects

Options

A. poultry
B. migratory birds
C. duck
D. all of these

Answer

### Step-by-Step Solution:

1. **Understanding Bird Flu**:
- Bird flu, also known as avian influenza, is a viral infection that primarily affects birds.

2. **Identifying Affected Species**:
- The infection is highly contagious and can impact various types of birds including poultry (like chickens and turkeys), migratory birds, and ducks.

3. **Analyzing the Options**:
- The question provides four options:
1. Poultry
2. Migratory birds
3. Ducks
4. All of these

4. **Determining the Correct Answer**:
- Since bird flu can affect all the mentioned categories of birds, the correct answer is "all of these."

5. **Final Answer**:
- Therefore, the correct answer to the question "Bird flu affects" is option 4: **All of these**.