Which of the following is a non-metal?

Options

A. Gallium
B. Indium
C. Boron
D. aluminium

Explanation

To determine which of the given options is a non-metal, we can follow these steps:

### Step 1: Identify the Elements
The options provided are:
- Option A: Gallium (Ga)
- Option B: Indium (In)
- Option C: Boron (B)
- Option D: Aluminium (Al)

### Step 2: Classify Each Element
Next, we classify each of these elements based on their position in the periodic table:
- **Gallium (Ga)**: This is a metal, specifically a post-transition metal.
- **Indium (In)**: This is also a metal, belonging to the group of post-transition metals.
- **Boron (B)**: This is a non-metal and is classified as a metalloid.
- **Aluminium (Al)**: This is a metal, specifically a lightweight metal in group 13.

### Step 3: Identify the Non-Metal
From the classification, we can see that:
- Gallium, Indium, and Aluminium are all metals.
- Boron is the only non-metal among the options.

### Conclusion
Thus, the correct answer to the question "Which of the following is a non-metal?" is:
**Option C: Boron (B)**.

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