Which of the following does not contain copper?

Options

A. German silver
B. Bronze
C. Brass
D. Duralumin

Explanation

To determine which of the following options does not contain copper, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Alloys:**
- We need to look at the alloys mentioned in the question. The typical alloys that contain copper include:
- German Silver: Copper + Zinc + Nickel
- Bronze: Copper + Tin
- Brass: Copper + Zinc

2. **Analyze Each Alloy:**
- **German Silver:** This alloy contains a significant amount of copper along with zinc and nickel.
- **Bronze:** This is primarily made of copper and tin, so it also contains a major portion of copper.
- **Brass:** This alloy consists of copper and zinc, indicating it also has a high copper content.

3. **Examine Dura Aluminum:**
- Dura Aluminum is primarily composed of aluminum (90-95%) and has only a small amount of copper (about 2-3%). This indicates that it does not contain copper in significant amounts compared to the other alloys.

4. **Conclusion:**
- Since German Silver, Bronze, and Brass all contain a significant amount of copper, while Dura Aluminum contains only a small amount, the correct answer is that Dura Aluminum does not contain copper as a major component.

### Final Answer:
The option that does not contain copper is **Dura Aluminum**.

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