How many electrons are in one coulomb ?

Charge of one electron is $1.602\times {10}^{-19} \mathrm{C}$. Total number of electrons that has 1 C charge:

$\mathrm{Number} \mathrm{of} \mathrm{electrons}=\frac{1 \mathrm{electron}}{1.602\times {10}^{-19 }\mathrm{C}}\times 1 \mathrm{C}=6.24\times {10}^{18} \mathrm{electrons}$

So, the correct answer is (c)