The SI base units and their physical quantities are the metre for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance.

Option C
Nothing to explain it bcoz it is universally accepted
but we can explain is at telling the units of that fundamental quantity
eg.meter for length and so on

Fundamental Units in the SI System

The SI system (International System of Units) is a widely used system of measurement that is based on a set of fundamental units. These fundamental units are used as the building blocks for measuring various physical quantities. In the SI system, there are seven fundamental units. Let's discuss each of these units and their significance.

1. Meter (m):
The meter is the fundamental unit of length in the SI system. It is defined as the distance traveled by light in a vacuum during a specific fraction of a second. The meter is used to measure the dimensions of objects, distances, and displacements.

2. Kilogram (kg):
The kilogram is the fundamental unit of mass in the SI system. It is defined as the mass of the International Prototype of the Kilogram, which is a platinum-iridium cylinder kept at the International Bureau of Weights and Measures (BIPM) in France. The kilogram is used to measure the mass of objects.

3. Second (s):
The second is the fundamental unit of time in the SI system. It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. The second is used to measure time intervals and rates of change.

4. Ampere (A):
The ampere is the fundamental unit of electric current in the SI system. It is defined as the constant current that, if maintained in two straight parallel conductors of infinite length and negligible circular cross-section, placed one meter apart in a vacuum, would produce a force between the conductors of exactly 2 x 10^-7 newtons per meter of length. The ampere is used to measure electric current.

5. Kelvin (K):
The kelvin is the fundamental unit of temperature in the SI system. It is defined as 1/273.16 of the thermodynamic temperature of the triple point of water. The kelvin scale is an absolute scale where zero kelvin represents absolute zero, the lowest possible temperature. The kelvin is used to measure temperature.

6. Mole (mol):
The mole is the fundamental unit of amount of substance in the SI system. It is defined as the amount of substance that contains as many elementary entities (atoms, molecules, ions, etc.) as there are atoms in 0.012 kilograms of carbon-12. The mole is used to measure the amount of a substance.

7. Candela (cd):
The candela is the fundamental unit of luminous intensity in the SI system. It is defined as the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10^12 hertz and has a radiant intensity in that direction of 1/683 watt per steradian. The candela is used to measure the brightness of light sources.