This metal is a liquid at room temperature :

Options

A. Potassium
B. Zinc
C. Gold
D. Mercury

Explanation

**Step-by-Step Text Solution:**

1. **Identify the Options:** The question provides four options: Potassium, Zinc, Gold, and Mercury.

2. **Understand the Question:** We need to determine which of these metals is a liquid at room temperature.

3. **Analyze Each Option:**
- **Potassium:** This is a soft, silvery metal that is solid at room temperature.
- **Zinc:** This is a bluish-white metal that is also solid at room temperature.
- **Gold:** This is a yellow metal that is solid at room temperature.
- **Mercury:** This is a heavy, silvery metal that is unique because it is liquid at room temperature.

4. **Conclusion:** Among the given options, Mercury is the only metal that is liquid at room temperature.

5. **Final Answer:** The correct answer is **Mercury**.

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