Which one of the following statement is true?

Options

A. A scalar quantity is the one that is conserved In a process
B. A scalar quantity is the one that can never take negative values
C. A scalar quantity is the one that does not vary from one point to another in space
D. A scalar quantity has the same value for observers with different orientaion of the axes.

Explanation

To determine which statement about scalar quantities is true, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Scalar Quantities**:
- A scalar quantity is defined as a physical quantity that has magnitude but no direction. Examples include temperature, mass, and speed.

2. **Analyzing Option 1**:
- **Statement**: "A scalar quantity is one that is conserved in a process."
- **Evaluation**: This statement is incorrect. While some scalar quantities can be conserved (like energy), not all scalar quantities are conserved in every process. For example, temperature can change in an adiabatic process.

3. **Analyzing Option 2**:
- **Statement**: "A scalar quantity is one that can never be negative."
- **Evaluation**: This statement is also incorrect. Scalar quantities can take on negative values. For instance, temperature can be negative in Celsius or Kelvin scales.

4. **Analyzing Option 3**:
- **Statement**: "A scalar quantity is one that does not vary from one point to another in space."
- **Evaluation**: This statement is incorrect. Scalar quantities can vary from one point to another. For example, temperature can vary from one location to another in a room.

5. **Analyzing Option 4**:
- **Statement**: "A scalar quantity has the same value for an observer with different orientations of the axis."
- **Evaluation**: This statement is correct. Scalar quantities do not depend on the direction of measurement. For example, the temperature at a point remains the same regardless of how you orient your axes.

### Conclusion:
The correct statement is **Option 4**: "A scalar quantity has the same value for an observer with different orientations of the axis."