A crest is the point of

Options

A. zero displacement
B. maximum displacement
C. minimum displacement
D. none of these

Explanation

To answer the question "A crest is the point of", we need to understand the definitions related to wave motion.

### Step-by-Step Solution:

1. **Understanding Wave Motion**:
- In wave motion, particles of the medium oscillate around a mean position. The motion can be described in terms of displacement from this mean position.

2. **Defining Crest**:
- A crest is defined as the highest point in a wave. It represents the maximum upward displacement of the particles from their mean position.

3. **Identifying Displacement Types**:
- In wave motion, there are different types of displacements:
- **Maximum Displacement**: This is the highest point (crest) or the lowest point (trough) that the wave reaches.
- **Zero Displacement**: This is the mean position where the particles are at rest.
- **Minimum Displacement**: This refers to the trough, which is the lowest point of the wave.

4. **Conclusion**:
- Since a crest represents the maximum upward displacement from the mean position, the correct answer to the question is that a crest is the point of **maximum displacement**.

### Final Answer:
A crest is the point of **maximum displacement**.

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