The system that contains the maximum number of atoms is

One mole of carbon atom weighs $12 \; g$. The number of atoms in it is equal to: (Mass of one carbon-$12$ atom is $1.9926 \times 10^{-23} \; g$)

The number of water molecules in $1 \ L$ of water is

$1.4 \, mol$ of phosphorus trichloride $(PCl_{3})$ are present in a sample. How many atoms are there in the sample?

$A$ thin layer of cobalt is deposited on a plate with a total area of $0.5 \ m^2$ and a thickness of $0.005 \ cm$. How many cobalt atoms are deposited on the plate? (Density of cobalt $= 8.9 \ g \ cm^{-3}$,Atomic mass of $Co = 59 \ g \ mol^{-1}$)

The number of atoms in $4.25 \ g$ of $NH_3$ is approximately