The base quantity among the following is

Options

A. Speed
B. Weight
C. Length
D. Area

Answer

To determine the base quantity among the given options, we will analyze each option in relation to fundamental quantities.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are speed, weight, length, and area.

2. **Understand Base (Fundamental) Quantities**: Base quantities, also known as fundamental quantities, are the basic physical quantities that cannot be derived from other quantities. The seven fundamental quantities are:
- Length (meter)
- Mass (kilogram)
- Time (second)
- Temperature (kelvin)
- Electric current (ampere)
- Luminous intensity (candela)
- Amount of substance (mole)

3. **Analyze Each Option**:
- **Speed**: This is a derived quantity calculated as distance (length) divided by time. Therefore, it is not a base quantity.
- **Weight**: This is the force due to gravity acting on a mass. It is also a derived quantity since it depends on mass and gravitational acceleration (Weight = Mass × Gravity). Hence, it is not a base quantity.
- **Length**: This is one of the seven fundamental quantities. It is a base quantity.
- **Area**: This is derived from length (Area = Length × Length). Thus, it is not a base quantity.

4. **Conclusion**: Among the options provided, the only base quantity is **length**.

### Final Answer:
The base quantity among the following is **length**.