The number of significant figures in $6.02 \times 10^{23}$ is

How many significant figures are present in the following?
$(i)$ $0.0025$
$(ii)$ $208$
$(iii)$ $5005$
$(iv)$ $126.000$
$(v)$ $500.0$
$(vi)$ $2.0034$

Among the following,the correct statement is

Find the number of electrons that generate $1$ coulomb charge?

The density of mercury is $13.6 \, g/cm^3$. Find the mass of $1 \, L$ of mercury. (in $, g$)

Choose the correct statements.
$A$. Weight of a substance is the amount of matter present in it.
$B$. Mass is the force exerted by gravity on an object.
$C$. Volume is the amount of space occupied by a substance.
$D$. Temperatures below $0^{\circ} C$ are possible in Celsius scale,but in Kelvin scale negative temperature is not possible.
$E$. Precision refers to the closeness of various measurements for the same quantity.