What is the minimum possible amount of charge?
A. Electronic charge e
B. Electronic charge 2e
C. Electronic charge $\dfrac{e}{2}$
D. Electronic charge$\dfrac{e}{{\sqrt 2 }}$

Hint : Here, we need to find out if anybody contains charge, what is the minimum quantity of charge it can carry. Electronic charge has been taken for comparison as charge is produced due to removal or addition of extra charge. Minimum amount of charge that can be removed is one electron as one electron is indivisible. Charge on one electron is $1.6 \times {10^{ - 19}}C$.

Complete step by step solution:
The most important concept that we need to know is that charge is quantized. It means that a charge can exist only as an integer multiple of electronic charge e. A charge cannot exist as a fraction of e as an electron is indivisible. Therefore, option C and D are eliminated as both state that minimum possible charge is fractional value of e.
Since the smallest integral value is one, we eliminate option B. option A is the correct answer which states that smallest charge which can possibly exist is equal to the charge of one electron $
   - 1.6 \times {10^{ - 19}}C \\
    \\
$

Note: Option A is the correct answer. A body can be charged with minimum about by either extracting one electron or by addition of one excess electron. The charge of one electron is $1.6 \times {10^{ - 19}}C$.Unit of charge is coulomb which is denoted as C. If one electron is extracted from a body, it acquires a minimum charge of +$1.6 \times {10^{ - 19}}C$. Similarly, if we add one excess electron to a neutral body it acquires a minimum negative charge of -$1.6 \times {10^{ - 19}}C$. This is because an electron carries negative charge.