What physical quantity does the electron volt ($eV$ ) measure?
A. Charge
B. Force
C. Energy
D. Current

Hint: The electron volt is not an SI unit; it is just opposite to the volt. It is a representation of a unit whereas the volt is the derived unit of electric potential between two ends. It is a common unit of measurement which is also used in solid state, atomic, and particle physics.

Formula used:
$E=qV$
Where: $q$ - elementary charge
$V$ - Potential difference

Complete answer:
An electron volt is the measurement of the amount of kinetic energy raised by an electron as it flows or passes through the potential difference of $1V$. So, the electron volt $eV$ is the unit to measure the energy.
i.e.
$E=qV$
$1eV=1.6\times {{10}^{-19}}C\times 1V$
Here: $q=1.6\times {{10}^{-19}}C$

So, the correct answer is “Option C”.

Additional Information:
Historically, the electron volt was devised as a typical unit of measure through its usefulness in electrostatic accelerator sciences, because a particle with charge q has an energy $E=qV$after passing through the potential $V$; if $q$ is quoted in integer units of the elementary charge and therefore the potential in volts, one gets an energy in $eV$. Astronomers use electron volts to live the energy of electromagnetic wave , or photons, within the x-ray and gamma-ray wavebands of the spectrum , and also use electron volts to explain the difference in atomic or molecular energy states which produce to ultraviolet, visual, or infrared lines,

Note:
It isn’t the SI unit to measure but it is used to measure the fundamental units of energy at very small instances, so don’t get confused between SI units and Fundamental units of energy. The SI unit of energy is joule, which is then related to electron volt as given relation:
$1eV=1.602\times {{10}^{-19}}J$