Choose the best alternative as the answer-
A pen always has

Options

A. Tube
B. Cap
C. Holder
D. Nib

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks us to choose the best alternative that describes what a pen always has. The options provided are tube, cap, holder, and nib.

2. **Analyzing Each Option**:
- **Tube**: A pen can have a tube, but it is not essential for all types of pens (e.g., fountain pens).
- **Cap**: Some pens have caps (like ballpoint pens), but others do not (like click pens).
- **Holder**: A holder is part of some pens, but it is not a universal feature.
- **Nib**: The nib is the part of the pen that allows it to write. Without a nib, a pen cannot function as intended.

3. **Determining the Essential Component**: Among all the options, the nib is the only component that is essential for a pen to fulfill its primary function, which is to write.

4. **Conclusion**: Therefore, the best alternative that describes what a pen always has is **nib**.

### Final Answer:
The best alternative is **nib**.

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