**Fundamental Physical Quantities in the SI System:**

The International System of Units (SI) is a globally accepted system of measurement that provides a consistent framework for scientific and technological communication. It is based on seven fundamental physical quantities, which are considered the building blocks for all other derived quantities. These fundamental physical quantities are:

1. **Length (meter, m):** It is the fundamental physical quantity used to measure distance or extent in three dimensions.

2. **Mass (kilogram, kg):** It is the fundamental physical quantity used to measure the amount of matter in an object.

3. **Time (second, s):** It is the fundamental physical quantity used to measure the duration or sequence of events.

4. **Electric current (ampere, A):** It is the fundamental physical quantity used to measure the flow of electric charge.

5. **Temperature (kelvin, K):** It is the fundamental physical quantity used to measure the average kinetic energy of particles in a substance.

6. **Amount of substance (mole, mol):** It is the fundamental physical quantity used to measure the number of particles (atoms, molecules, etc.) in a substance.

7. **Luminous intensity (candela, cd):** It is the fundamental physical quantity used to measure the intensity of light emitted by a source in a particular direction.

**The Non-Fundamental Physical Quantity:**

The physical quantity that is not considered a fundamental physical quantity in the SI system is the **solid angle**.

**Solid angle (steradian, sr):** It is a measure of the extent of a cone-shaped region of space as seen from a point source. It is used to describe the angular extent of a solid object or the field of view of an optical instrument.

The solid angle is a derived quantity that can be calculated from the fundamental quantities of length and area. It is defined as the ratio of the area on a sphere's surface to the square of its radius. While it is an important quantity in certain fields, such as optics and astronomy, it is not considered a fundamental physical quantity in the SI system.

In summary, the solid angle is the physical quantity that is not a fundamental physical quantity in the SI system. The SI system recognizes length, mass, time, electric current, temperature, amount of substance, and luminous intensity as the fundamental physical quantities.

Ans)C
Solid angle is a supplementary unit