Which of the following are fundamental quantities?

Options

A. mass
B. length
C. time
D. all

Answer

To determine which of the following are fundamental quantities, we need to understand what fundamental quantities are. Fundamental quantities are those that cannot be derived from other quantities; they are independent and serve as the basic building blocks for other measurements.

### Step-by-Step Solution:

1. **Define Fundamental Quantities**:
- Fundamental quantities are basic physical quantities that cannot be expressed in terms of other quantities. They are independent and serve as the foundation for other derived quantities.

2. **List the Fundamental Quantities**:
- There are seven fundamental quantities recognized in the International System of Units (SI):
1. Mass (kg)
2. Length (m)
3. Time (s)
4. Electric Current (A)
5. Temperature (K)
6. Amount of Substance (mol)
7. Luminous Intensity (cd)

3. **Evaluate the Given Options**:
- Check each option to see if it is one of the fundamental quantities listed above:
- **Mass**: Yes, it is a fundamental quantity.
- **Length**: Yes, it is a fundamental quantity.
- **Time**: Yes, it is a fundamental quantity.
- **All**: Since Mass, Length, and Time are all fundamental quantities, this option is also correct.

4. **Select the Correct Answer**:
- Since all the individual options (Mass, Length, Time) are fundamental quantities, the correct answer is "All".

### Final Answer:
The correct option is **D. All**.

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